You could not be farther from the truth. Gitlab is an improvement on Github in every way, they offer a suite of features that Github doesn't have that are only available through third party connections.
I used to work stock at a bunch of retail stores for a decade and could see what percentage the markup was. It was almost never above 20%, and usually closer to 3-5%.
What I was seeing was the same in both cases. Firefox would be using the same amount of RAM either running by itself or alongside Ableton Live (and the performance of Ableton Live would suffer).
I'm a front end and back end developer that uses multiple libraries and tech stacks and need to find answers to stuff immediately. I leave them open as a resource while I'm working, which may be on multiple things at once. In addition, I have mail, messaging, music, and other work-related things open in the browser.
It's really one of the only features that matters.
I was having the exact same issues on Twitch allll the time on FF on Mac. I haven't since switching to Vivaldi, probably have frozen two or 3 times since.
I'm an avid, avid, avid Firefox user, but I switched to Vivaldi last month after doing a comparison of RAM load with the same exact open tabs and seeing a difference of:
Firefox sitting at 12 gigs
Vivaldi sitting at 5 gigs
This is on MacOS, so mileage may vary and all that, but with the same tabs open, why would there be such a difference?
Edit: And there's no difference in the plugins. I use the same plugins on both browsers: password manager, uBlock Origin, React dev tools, and Redux dev tools and that's it.