Maybe it's an odd-number issue with the Pixels? My wife is using my old Pixel 2 with reduced battery life, but otherwise no issues. My Pixel 4 XL is still working great.
I've had Pixel XL, 2XL, 3, 4XL and 5. They've all worked 3-4 years (I pass them on to various members of my family). The only one I had any issues with was the 4XL, with the back plate peeling off, and Support just swapped it for me after 5m online chat.