I’m gonna be that person…

Well, you are not alone. While I too would prefer not to use proprietary drivers, I have had no problems on any of my Nvidia machines as well. Ironically, despite the open source drivers, getting a 7900XTX card up and running was an issue for me for months till distros caught up (with newer kernels and mesa libs), while my 4090 installation was a breeze even on the day it was released.

A lot of problems people have with Nvidia GPUs seem to be installation related. I think that is because the installation tends to be distro-specific and people do not necessarily follow the correct procedure for their distro or try installing the drivers directly from the Nvidia site as they would on Windows. For example, Fedora requires you to add RPMFusion, Debian needs non-free to be added to sources, Linux Mint lets you install the proprietary drivers but only after the first boot, and so on. Pop OS! probably makes the process the easiest with their Nvidia-specific ISO.

Minimal issues here. Set up Arch, install nVidia, add build hooks before next kernel update, carry on.

Same. I had an Nvidia 960 for about 5 years on arch with very few problems. Maybe twice over that time I had to rollback to an older version temporarily due to some incompatibility with wine or such like.

Towards the end of last year I finally decided to upgrade (mostly to play RDR2) and I went with AMD. I love the feel of using a pure open source gfx stack, but there is no real functional advantage to it.

I have a 3080 and it runs fine with openSUSE Tumbleweed. On first boot you do need to add the nvidia repo and then install it which I guess could be problematic for new linux users, but it's literally pasting 1 line into terminal and then clicking the driver in yast. Echoing what others have said, I'd prefer if nvidia was a little less hostile to open source but frankly the driver just works, and works well. The only thing I've used besides openSUSE lately is Pop_OS and I believe the nvidia driver was installed automatically. If someone is having trouble getting the driver installed that seems to be a failure of the distro, not the user. You should be able to depend on your distros packaging to take care of this stuff.

There is definitely some substance behind the complaints, but I think they are overblown or just the typical linux-user-parroting something they heard other people say.

On PopOS my 3070ti was always stable. I ran into occasional stuttering in the DE, but the biggest thing was I had to manual compile shaders using some guys github repo to play Apex Legends without it being a stuttery mess. But like you said, Pop is on X11 so maybe that makes a difference?

I bought into the "if you are going to use linux, especially for gaming, you need an amd gpu." So I bought a 6900xt. I've had as many issues with my 6900xt; they are just different types of issues. Nothing insurmountable but its not like its some panacea.

is it because I’m happy staying on X11?

I think this is a big part of it. I have no issues with Nvidia + X11, however if I try to use Wayland with my 2080 I get numerous issues that has me running back to Xorg very quickly.