Right now I am testing Kagi, which is a paid alternative - from a privacy point of view, it looks great, and the results are good. It also has a lot of additional features that suit me well. No Maps integration though. alternatively, I can recommend SearXNG, but it involves a bit of tinkering.

For desktop use I would recommend Raspberry Pi OS too - if it is going to be for desktop use, I found that using the option to boot directly from an SSD (if available) gives it a bit of extra smoothness.

Indeed, if I were the developers I would be threading much more carefully. While it may be true that the letter is not precise enough, access to YouTube implies a relative acceptance of the terms of service of providing the service, and it is not so clear cut as Invidious claims.