It never worked well on the R5 for me. There's always a few photos (5-10%) missing GPS info at the end of the day. I have a backup logging app on my phone so I can fix it after the fact, but it's annoying.
I make sure to have all the permissions enabled, launch the app in the foreground, etc and it generally does work but just isn't reliable. Whereas every single iPhone photo is properly tagged, so clearly it's possible.
And once in a while I'll forget to take the R5 out of airplane mode and get no GPS tags at all. My fault sure, but without it the battery is dead after a few days. Taking out the battery and transporting them separately helps, but is also cumbersome.
I'd take built-in GPS even if the total camera battery life was halved! For personal use it's just really useful to search by location, especially across different cameras.
And don't get me started on the GP-E2! Shame on Canon for still selling such a dinosaur of technology, at such a size and high price. It's 12 years old! With today's tech it would be possible to make it a lot smaller, lighter, faster, less battery-intensive, and more accurate. GPS running watches have come a long way in the same time, and can now provide all day GPS in a very small package.