Codeberg does suffer from the occasional DDOS attack—it doesn't have the resources that GH has to mitigate these sorts of things. Also, if you're across the pond, then latency can be a bit of an issue. That said, the pages are lighter weight, and on stable but low-bandwith connections, Codeberg loads really quickly and all the regular operations are supper zippy.
I hear you and you're right that Codeberg has some struggles. If anyone needs to host critical infra, you're better off self-hosting a Forgejo instance. For personal stuff? Codeberg is more than good enough.