Ah, darn. Unfortunately I have no additional help to offer since that particular issue was fixed for me after changing those options in Flatseal.
I’d try running Firefox from the terminal to see what error message you’re receiving when the crashes occur; the unique error message was what led me to this workaround when I was originally troubleshooting.
I’ve been really happy with Bazzite on my laptop the last few months, although I seldom game these days.
My wife’s Windows laptop stopped working recently and I haven’t been able to repair it, so she’s been gaming on my laptop in the meantime. So far it’s been able to play everything she’s thrown at it without issue.
I’m sad that I haven’t been able to fix her laptop, but I’m kinda happy cause it means there’s no longer any Windows machines in the entire house, lol.