Just fyi, I found this fix here on the archwiki. With it I’m not seeing any issues any more. That’s with the Ryzen 5 7640U on Ubuntu 24.04, standard kernel (6.11 series atm).
Since using mainline to update 25.04 to the 6.14.4 kernel, I’ve not had a single hang, from cold boot. Still happens (rarely ?) post-resume from suspend-to-ram.
I don’t have any boot arguments, or updated mesa.
I am using FireFox from the Mozilla repo, rather than the included Snap