devops sysadmin here. I started with gitlab about a year ago and can honestly say I wish I had taken gogs/gitea instead. The main problem for me is gitlabs utter dearth of somewhat counterproductive features. Git LFS support is almost a cruel joke in gitlab as git operations under the hood now take inexorably more ram to complete. In turn im rewarded with more traditional RCS programmers asking why git has problems with their newly requested LFS and a 40gb video file they decided to store.
gitlab is also so large it requires its own chef deployment to competently install it from omnibus, and has no HA roadmap in sight unless you want to break apart its rube-goldberg structure and attempt to HA the individual components of it.
Other things like Wiki, local runner CI, pages and integration with a corporate Jira ticket system seem like the excessive demands of programmers without enough skill to understand that there is tangible merit in ablating these systems into separate applications entirely and growing them as needed. gogs and gittea allow you to put the brakes on developers that just want to get the code out the door in order to study and implement competent things like competent CI, blue/green deploys, immutable infrastructure and reproduceable builds that target scalable platforms like Kubernetes instead of one-offs that just reward coders with a merciful standup and the chance to say "its done."
if you use gittea for no other reason, it is also massively less resource hungry than a gitlab installation. im currently throwing 4 cores and 8 gigs of ram at my gitlab install with another 2.3tb of disk and frankly no end in sight. The gitlab rake task for backups has sent oomkiller on a rampage 3 times so far and takes forever. Large installs of 1000 users or more and you'll begin to see why gitlab might not be the best choice. with programmers, the thirst is real...nobody cares about features if the repo wont clone.