IMO it might be just a product problem. I opened nebula and:
* The same video had a better title on YT that was actually less clickbaity and more informative - assumedly because of YT algorithm for optimization
* Nebula auto set quality to 480p compared to 1080p in YT - if I wasn't tech-savvy I'd assume it's just worse quality.
* The loading times when you seek to part that's not loaded yet are 10x longer
* I missed comments
The recommendation algorithm is weaker too, I can't tell to what extent this is due to YouTube having simply more data and to what extent it's weaker engineering.