My experience with contributing to gitlab has actually not been as you describe. Fairly fast responses, obviously targeted releases so I knew when to try and finish any Mr adjustments, bots that provided excellent aid and even ability to ask for subsystem specialist help, when CI shot out confusing errors that appeared unrelated. Frankly, I was impressed. I understand not every feature or bug would go this way, but if you follow their guidelines, get product road map positioning, it works. The amount of commits going in to main are incredible. The number of MRs they handle is equally impressive.

All of that said, I've still got issues in gitlab that are seven+ years old, without any movement. But I get it that they have to prioritize and contributions are a different story.