In this case, the someone else is Alphabet megacorp. I wouldn’t waste any concern on them. The content is still hosted by YouTube, just played through the invidious instance.
To do away with all those concerns, you could self-host invidious, or donate to the instance you choose to use if self-hosting is outside of your technical prowess. If you want to support certain creators, donate to them directly instead.
In this case, the someone else is Alphabet megacorp. I wouldn’t waste any concern on them. The content is still hosted by YouTube, just played through the invidious instance.
To do away with all those concerns, you could self-host invidious, or donate to the instance you choose to use if self-hosting is outside of your technical prowess. If you want to support certain creators, donate to them directly instead.