Sourcehut doesnt require your users to have an account to submit issues or patches. All you have to do is have an email account and send an email.

https://sourcehut.org/

When compared to selfhosted gitlab/gitea/etc. it is ideal since it encourages decentralization while not having a cumbersome first time setup for selfhosted instances.

Oh, and it's 100% free software. No open core stuff.

Oh and I trust Drew to not do stuff like this https://news.ycombinator.com/item?id=27724008