If Alpine prides themselves on focusing so much on security, they probably shouldn’t use GitLab - the attack surface is too great and it’s never going to be easy to keep safe and up to date fully, unless you have FTEs whose main job is just maintaining it.
Just get the source code of Forgejo, audit it thoroughly and run an instance of that.
Thinking that Forgejo is a viable replacement for someone who uses GitLab is wild. It's a bit like telling someone to use cgit instead of Forgejo. (yes I know Alpine uses cgit as well)
Didn’t Forgejo have a crit in pretty much all versions recently https://news.ycombinator.com/item?id=49645907
I like Forgejo btw, but these days everything is vulnerable. Switching tools isn’t the final answer