1. Looks bad, but what about the other mainstream options such as Tuta ?
2. True but I do think it will get noticed pretty quickly but probably not fast enough.
3. For weeks ? I know new products are always proprietary closed beta but didn't knew that...
4. I think it's pretty fair as it is a freemium service, paid user needs to get rewarded for paying.
5. Yeah I prefer to endorse free and open solution rather than closed garden wall, even if they are published under open source licence, but in the other hand It seens like there is a demand from the market for a privacy-respecting ecosystem that offer a similar experience to Google for exemple.

There is no such thing as a perfect solution or perfect security. Depending on your threat model I do think Proton isn't a bad option, maybe it's not the best but as of today all the honeypot claims seems to be simply FUD. Your worries are legit but I'm pretty sure you can have similar worries for other products that you use and feel safe using them.