Ease of maintenance is an even bigger difference. We've been using gitea for a bit over five years now, and gitlab for a few years before that, and gitea requires no maintenance in comparison. Upgrades come down to pulling the new version and restarting the daemon, and take just a few seconds. It's definitely the best solution for self-hosters who want to spend as little time as possible on their infrastructure.
Backups are handled by zfs snapshots (like every other server).
We've also had at least 10× lower downtime compared to github over the same period of time, and whatever downtime we had was planned and always in the middle of the night. Always funny reading claims here that github has much better uptime than anything self-hosted from people who don't know any better. I usually don't even bother responding anymore.
When I self hosted gitlab I never found the maintenance to be that bad, just change a version in a compose.yml, sometimes having to jump between blessed versions if I've missed a few back to back.
Like others, I've switch to Gitea, but whenever I do visit gitlab I can't help but think the design / UX is so much nicer.
I found gitea's interface to be so unusably bad that i switched to full-fat GitLab.
Gitea refused to do some perfectly sensible action- I think it had something to do with creating a fork of my own repo. Looking online, there's zero technical reason for this, and the explanation given was "this is how GitHub does things". Immediately uninstalled. I'm not here for this level of disrespect.
I guess I'll just chime in that while Gitlab is a very heavy beast, I have self hosted it for over a decade with little to no issues. It's pretty much as simple as installing their Omnibus package repository and doing apt install gitlab-ce.