I have been using a T495 since spring 2020 and only after upgrading to Fedora 39 in December have I been able to run it without having to reboot at least once a day due to the amdgpu driver hanging up.
I will say "Here There Be Dragons" wrt CUDA/OpenCL workloads however. You have to switch from Mesa to the AMD closed source drivers, and I did have some wonky issues, with, for example using things like Davinci Resolve with those drivers.
On the other hand, my AMD Framework 13 hasn't had any issues with the iGPU with Linux. (It bluescreened and rebooted twice in two months with Windows, and I suspect both of those were graphics-related, but no issues in the month or so I've had ubuntu on it.)
The P14s seems very fast and stable with Fedora 39. I tested OpenCL as well as Steam games and general desktop usage with Firefox.
But to be honest, I didn't have as much trouble as you describe with my T495 either. I ran it exclusively with Fedora since right before the pandemic. My main problem was that I could not use OpenCL at all. But for desktop usage and even Steam games, it worked well enough.
I'll admit I rarely use suspend/resume, so if your problems were related to that, it might explain my different experience. I've noticed the T495 is very slow to resume compared to most other machines I've used including the P14s and lots of Intel-based Thinkpads.
I've had excellent experience with amdgpu and the vega integrated graphics.
There's a second driver amdgpu pro that might be worth a look though I've never used it.
FWIW, most of the issues happened with an alt mode display and/or USB-C dock plugged in. Very few issues when undocked, but as it is a work machine, it's not going to be used by itself too much. In any case, I've lost more productivity than the price difference to the equivalent Intel model laptop would have been.
IIRC, the last time I tried using Wayland, my nVidia GPU was the barrier.