How can I have my game login to my server using users steam ID to do things like store replays, etc?

I’m currently using VARest and a django(rest framework, python) server - Also “Advanced steam sessions” for multiplayer.
Having said that - I am interested in answers for any language/stack.

Question is in the title really - Ideally I’d like the game to be able to securely login without any extra user-input.

I’ve had a bit of a look around, and not found a good answer - I’m guessing I setup a normal steam oauth serverside, the clientside “somehow” logs in using this (I also suspect this may not be dooable using pure BP, happy to jump over to CPP if needed)