Anarchism

You don't, the accumulation of wealth is a zero-sum game. There's no way to "win" that doesn't involve others losing.

Plus, nobody gets rich by honest labor. Your ethical friends are almost as far from actual riches as the rest of us. Even I "Work with hundreds of millions if not billions" and my paycheck barely covers the bills every month.

What you're asking for is a demarcation between the bourgeois and the petite-bourgeois, but the difference is only one of scale. Small business owners enrich themselves with the profits their employees produce, while Bezos and Musk have a thousand times more employees to exploit.

It sounds like the people you've used as an example certainly try to do good.

I think an issue here is that "ethical" and "unethical" as value judgements operate on many different levels and just because someone does something considered one or the other, it doesn't necessarily mean they are wholly bad or good.

Providing services aimed at helping poor and marginalized people? I'd argue that's ethical.

Accumulating wealth? I'd argue that's unethical, whether it's by doing something helpful or harmful: as another commenter pointed out, it's a zero-sum game and keeping more for yourself means there is less for others.

I don't think the people you described are bad people; they're doing something philanthropic within an unethical system.

Tldr: basically there are owners and workers. (this is of course leaving out all of the people who can't or don't work or work outside of wage labor but that is not what we are focusing on right now). In an ideal world there would not be people who "profit" off of the labor of others.

That is not to say people cannot work together make each other's lives better and enrich each other, but it wouldn't be in a owner/worker relationship, it would be in a co-worker/community relationship. If your friends own a business and make the lion's share of the profit while employees who enable them to do their work only get a small share of the value created by their labor, they may be trying to help but they are still exploiting their employees for profit. A truly equitable company would need to have all workers treated equitably and no profit be generated for shareholders. This is 100% possible but it's definitely not the standard model people are taught.

I believe what people mean when they say there is no such thing as a good billionaire is, it is impossible to create that much personal wealth without exploiting others and, furthermore, amassing that large an amount of extracted wealth is inherently harmful to the exploited workers on such a level as to be undeniably evil. You cannot gain that much wealth without explicitly and intentionally stealing from those who created it. Even people who work hard, who could be argued are the only reason that wealth is generated, (thinking of Taylor Swift here) if they were truly good people they would see the profits that are being made by the Enterprise that they spearhead and know that it would be impossible without the people who work with them and support them to create that wealth and that it should be distributed as equally as possible between all involved. If they are keeping such a large portion that they become a billionaire, they are inherently evil, regardless of if that wealth could have been created without them.

I suppose there could be some argument for a theoretical company that was so profitable that all employees involved in creating the value reached billionaire status, but I have a hard time imagining any business that could create that amount of wealth without their business being exploitative in some way, even if all parties involved in that business directly are paid equally. An example of this might be a investment brokerage. People who invest in the stock market and get rich doing so are not employers directly but they are indirectly, through the stock market, siphoning the value of exploited workers from corporate profits.

This topic is of course a ethical and idealistic one. Expecting everyday people who have invested in the stock market through their 401k to not use the wealth that they receive from those investments to live comfortable lives In their retirement would be ridiculous in our current system. In an ideal world that wouldn't be necessary, people would be guaranteed food, housing, and healthcare for the entirety of their old age and retirement without requiring the explicit exploitation of wage labor, but there must be a division in our consciousness between what an ideal person in an ideal world would do and what an an evil person in our current world does and that it is the gray in between those two extremes that makes up the vast majority of the current population.

One last point to consider is that developing class consciousness is something that needs to be taught and learned and understood and that the current societal expectations and norms that we have instilled in us from a very young age need to be broken down internally before people are able to recognize how much harm the current system does. I guarantee that the people who profit the most off of their employees believe wholeheartedly that they are doing good by creating jobs for people who otherwise would have had nothing without the company that has been provided by their ownership. Getting people who benefit the most from our current system to see how harmful their "good fortune" is to others will be a daunting and thankless task and will take decades.

I think you should start out reading some anarchist theory, like The Conquest of Bread by Kropotkin, rather than try to use it to label people evil or good.

It's not a tool to judge people's goodness or badness, even if it can be used as a guide to judge the relations between two people.

Your friends accumulation of wealth probably doesn't jive with anarchist principles for a wide variety of reasons, even if they don't exploit labor. That doesn't mean they're evil people. And just because someone exploits labor, doesn't mean they are necessarily evil.

How can one clearly define someone like Musk or Bezos as bourgeois whereas these hard working individuals who came from nothing and build a huge business actually from nothing and help people?

musk and bezos are not "bourgeois"! Oligarchs maybe?

When bourgeoisie ruled the world, they would only in their wildest dreams could make believe that one day so much capital would concentrate in the hands of one or two greedy assholes. Musk is a historical abomination that needs a class of his own. (he would probably take this as a compliment!

Not so useful to separate them, better not enable the evil ones in the first place.

Laws should reward only the ethical value making, not the money hoarding:

• ~100% inheritance tax. No unearned rich anymore. Funds universal basic income.
• Intellectual property (patent, copyright) owners can't forbid others from producing, and state decides the cut the owner gets according to simple formula. Patent trolling and sitting on inventions made impossible.
• Ban artificial scarcity: All trade secrets must be published as patents. Every computer must have everything digital ever made. State decides the producer's reward based on consumption times value produced while consumed. When addiction produces negative value, harm tax funds harm reduction and the producer is fined.