Many users have reported the issue being caused when running Discord screen share alongside the game, which is something that has been stated as incompatible, according to the Forza Horizon 5 support page.
Forza Horizon 5 players have been reporting a bunch of crashes on the PC version specifically.
The support page lists a number of programs such as Discord, MSI Afterburner, OBS, and XSplit, among a few others, as being potential reasons for the game to enter a fail state.
Hopefully, Playground Games does the needful at the earliest to resolve any issues that get in the way of that.