Proton are very transparent about what data is and isn’t stored, how data is protected and what (very limited) data may be available in the event of a legal warrant - going through all the proper channels.
Complying with legal warrants doesnt make the service insecure or not private. It makes it a legal and legitimate company.
It shouldn’t really be a surprise to any of it’s users.
UK is pretty far from perfect but to suggest we have “just as dubious morals” as China is categorically wrong.