I’ve mostly tried Fedora 40, I gave it another quick go after 41 with no improvement. Given that most other people haven’t experienced it, and I’ve only had this issue with Tumblr specifically and no other website, I’m guessing that it must be an uncommon codec.
I was using Firefox. I don’t expect Tumblr to be well coded, but at most it should be able to freeze a single browser tab, if a tab can crash the entire desktop then that’s a greater issue. I haven’t had issues with tumblrs infinite scroll on other desktop situations, and while the crash happens at random I’ve had it happen within 30 seconds of opening a site if there’s a video first thing. The dmesg logs indicate that the GPU driver gets upset about something and resets itself at the time of the crash.
Trying the Firefox flatpak, or not installing the nonfree drivers didn’t make any change for me.
When looking at past reports of the crash I’ve seen some people report that things are fine on chrome but I’m not willing to make the change to see if that helps haha. It’s not a massive deal but it bugs me that I have to remember what websites to ignore and I want an expensive laptop to be a stress free experience so I’ll stick with windows and maybe give Linux another try every year or so to see if they can tempt me over yet.