Being open sores wont save a project from being dead especially when the main lead. You would know why if you actually write code and worked in a project.
It could have been compensated if invidious had a larger dev team but all it has are two devs. Just go check out their issues page in github and see all these months long open issues and bugs if you want to understand what I'm saying.
Newpipe doesn't use invidious. It crawls youtube directly to get the video and audio streams using its own self developed API. It even started way way before invidious, has a much larger dev team and more matured as a project. Newpipe even combines lower resolutions streams with the audio, something that even invidious cant do hence why all invidious videos other than 360p and 720p are soundless. Just because it can open invidious videos dont mean its using invidious.
If you want a web version of new pipe check out rustypipe but its in heavy alpha stage.