Technology

And seemingly reading beyond the headline is also not your thing.
This is a separate app unconnected to your bitwarden account...

Exactly, from a security perspective, it's a bad idea to put 2 factor tokens together with your passwords. You effectively eliminate the security benefit that 2 factor provides if you do because if people get into your password manager, they have everything they need to access your accounts. The only people it "helps" having it all in one app are people who don't understand the purpose of 2 factor and just see it as an inconvenience when services force it on them. Even though I use BitWarden for passwords, I don't think that I'll be changing from Aegis to BitWarden's stand-alone authenticator because Aegis is doing its job nicely.

Not yet.
No icons, no ability to save notes, a URL or back it up in an encrypted json.
I will definitely keep an eye on it though.

You can use Authenticator Pro (android, opensesource) and Proton Pass, both let you copy the TOTP generation code to paste into another without problem. Both generate exact code

In fact that's how I am using them right now, with Authenticator Pro is my on-device, offline, encrypted backup offline backup TOTP for Pass.

I guess it is not as straight forward as export import as you hope, but it's not as bad as other options used to be.

As long as you can access the keys, you can swap authenticator apps.

I tried a few until I landed in Aegis, and I have two on my desktop that I'm trying out as well. Just get something that allows exporting the keys and there will be a path to switching apps.