(Not to be confused with Outline, which is already in the apps list)
I’ve just discovered Outline VPN, which seems like it would make a good addition to Yunohost. I don’t know if it would be feasible or manageable, but thought I’d post here for further investigation if it is of interest.
It is open-source and seems to run on Linux-based servers. I’m not 100% sure but it may be able to use cloud hosting with Nextcloud if a user has that set up on their Yunohost server as well.
A downside is it’s made by Jigsaw, a “unit within Google”. Outline’s privacy policy is available here.