It’s fixed in 6.8.10 and 6.9 if you have the ability to upgrade to those.
Honestly idk how id even begin to do that lol, and id also maybe rather not start my first week of linux use by immediately trying to change the kernel version on my own XD (either down or up). I did hear about an issue with rdr2 and kernel 6.8.9 from a reddit post which i found through someone writing about problems with the game on its protondb page. But i thought i was fine as my game worked normally until i encountered the crash & because the reddit and protondb post say its solved by enabling rebar which (iirc) i already have.
However idk if that reddit posts issue is the same/related to the one you linked. Since the rest of the game and my system seem to be mostly fine i think ill either just not play the game or specifically avoid the cutscene when i do (its in an optional quest luckily). And then ill maybe return to it after the updated kernel arrives on fedora to see if it solves the crash or not.