If they're moving away from open source/more monetisation then they're going to do one of two things.
1: Make the client incompatible (e.g you'll need to get hold of and prevent updating of a current client).
2: DMCA the vaultwarden repo
If they're going all-in on a cash grab, they're not going to make it easy for you to get a free version.
Just post that you think it'd be impossible to port to rust and linux. Then someone is bound to do it :P