A few days ago, I made a ticket on riot support asking some questions about Vanguard on LoL. I will post Linux related questions in this post. The full questions and answers will be in the comments.
TLDR: Vanguard is not coming to MacOS (implied in answer, ~~awaiting confirmation~~ Confirmed, Vanguard is not needed to play LoL on MacOS), Riot doesn't know whether unofficial Linux support through proton will continue. Get your Darling ready!
Q: LoL currently works fine on Linux under proton, but with the proposed changes, LoL will stop working on Linux. Although Riot has stated that they probably will never natively support Linux, Riot has worked with the Linux community in the past to make LoL function under proton. Does Riot plan on continuing this line of communication with the Linux community to attempt to bring Vanguard to Linux as well (maybe not natively), or will Riot cease to support LoL on Linux at all? (even unofficially?)
A: As far as Linux goes, virtual machines have almost never been a supported practice as far as we know, and they're known to cause crashes and issues in general. The only support was the one you mentioned - proton, and we can't say for certain whether or not it will be a continued one.
Q: There is currently a version of LoL for MacOS, but Vanguard is currently unavailable for MacOS (Riot’s reason for why Valorant is not supported on MacOS), what does Riot plan to do about this (Will Vanguard be coming to MacOS)?
A: Players using Mac will still be accountable for cheating, getting account bans if detected (but not hardware bans), and they’ll also experience match terminations if someone else is detected.
Full questions and answers:
Q1: Would it be possible for Riot to provide more technical information or documentation on Vanguard? The information that is currently available is quite vague.
A1: Riot Vanguard is Riot Games’ custom game security software, designed to uphold the highest levels of competitive integrity for our games, this software was originally included with VALORANT, and due to its effectiveness we’re now implementing it with LoL and TFT. This will bring even more benefits like terminating the match if a cheater is detected, so your progress doesn’t get affected by another player trying to get an unfair advantage with cheats or scripts. It was made with Riot Games' dedication to data privacy specifically in mind, and we worked with our legal and compliance teams to ensure it adheres to regional data privacy laws. Vanguard does not collect or process any personal information beyond what the current and soon to be deprecated League of Legends anti-cheat solution does. Specifics on what data we use and collect are available here. That's as much info that we can share when it comes to the anti-cheat, gamer.
Q2: Will Vanguard have a significant or noticeable impact on performance, especially on lower-end hardware? Is there anything that players can do to optimize their system to reduce the performance impact of vanguard?
A2: Player Support can't really tell you if Vanguard will have any impact on your performance, however from personal experience I can tell you that by playing VALORANT I didn't feel any issues with my FPS, nor gameplay. Knowing that anti-cheat programs work on a similar principle like anti-virus software, it could take some processing power while scanning for malicious programs.
Q3: There is currently a version of LoL for MacOS, but Vanguard is currently unavailable for MacOS (Riot’s reason for why Valorant is not supported on MacOS), what does Riot plan to do about this?
A3: Players using Mac will still be accountable for cheating, getting account bans if detected (but not hardware bans), and they’ll also experience match terminations if someone else is detected.
Q4: LoL currently works fine on Linux under proton, but with the proposed changes, LoL will stop working on Linux. Although Riot has stated that they probably will never natively support Linux, Riot has worked with the Linux community in the past to make LoL function under proton. Does Riot plan on continuing this line of communication with the Linux community to attempt to bring Vanguard to Linux as well (maybe not natively), or will Riot cease to support LoL on Linux at all? (even unofficially?)
A4: As far as Linux goes, virtual machines have almost never been a supported practice as far as we know, and they're known to cause crashes and issues in general. The only support was the one you mentioned - proton, and we can't say for certain whether or not it will be a continued one.
Q5: Will overlay applications like blitz.gg, u.gg, porofessor, mobalytics, etc. be affected by the addition of Vanguard?
A5: Even though we don’t strictly condemn the use of third-party modifications, these programs can be dangerous and worthy of suspension where they violate our Terms of Use. I can’t tell you whether game performance trackers are against our Terms of Use or not, but you can follow these general guidelines:
All in all, if you find a third-party modification suspicious, it’s best to avoid using it.
Q6: Will Riot provide a roadmap for the technical development of Vanguard and platform compatibility issues in the near future?
A7: While we can't tell you for certain whether or not a roadmap will be released, you may check the News Page which includes updates due to the fact that Riot hasn't shared that info with us either, and if one gets released, it will most likely be posted in there! ^-^
These answers are sooo vague. (~~I will edit this when confirmation for MacOS is given~~ Vanguard not needed on MacOS)