I did a bit of investigating, and it's going to cost so much more to get it on Steam than anywhere else!
What is the Rockstar Launcher like? I could also get it on Epic Launcher for the same price, but I've never used that either...
Epic is my favourite launcher. It seems very realiable and they give away a free game each week. This week is world war z.
I got borderlands 3 and red dead on there and play a lot of both and haven't been disappointed.
Where ever you get the game from it will still run rockstar launcher in the background. The epic launcher handles this perfectly and will sign you in automatically without any issues.
I have never liked using rockstar launcher directly because they use them CAPCHTA things on everything.