It looks like despite launching on Steam, Red Dead Redemption 2 is suffering issues.
The issues mainly stem from crashing when starting, or crashing when plugging in a controller. These were remarked on in Steam reviews.
“Crashes for me! :Wont start. Out of hundreds of games I have downloaded on steam. This is the first one that will not start and states to contact Rockstars games for support. I waited to buy this specifically on Steam and the Rockstar launcher doesnt work through Steam.”
He later commented that unplugging the controller actually seemed to fix it. These issues seem to stem from the fact that, despite launching on Steam, the game still needs to open Rockstar Games Launcher in order to run.
“Game opens the rockstar launcher. Rockstar launcher says I own GTAV but have to buy RDR2 Cant seem to activate my ---ing game”
As of this writing, Rockstar hasn’t addressed the Steam crashes yet, but given how they’ve been rapidly patching the Rockstar Games Launcher version, one hopes that same expediency is given to the Steam version, even though it could be said that after a month, one would expect a secondary launch to go smoothly.