As long as it stays FOSS, you don't need to worry. You can even self-host Standard Notes if you don't trust their cloud service: https://standardnotes.com/help/self-hosting/getting-started

RapidSeedbox they accept multiple crypto currencies but unfortunately no XMR, so I had to use Trocador to convert to BTC.

It's not perfect, there are some conversion fees, but it should be ok. I use it from time to time to pay for my seedbox.

Obsidian is pretty good, it shouldn't collect any data by default. But you can also check out Logseq, an open source Obsidian alternative.

Same, but you can always use Trocador to convert your XMR to other coins. Alternatively there are some ways to anonymously acquire BTC.

Yes. The NewPipe x SponsorBlock repo is archived and there's a message in the README saying:

Development Has Stopped

This fork is old and no longer maintained. See Tubular, a new fork of NewPipe.

BitLaunch lets you rent a VPS with crypto currency

https://kyun.host/

Well technically that's not part of the compiler

rustc is truly awesome

Finally a use case where AI/Machine learning would absolutely make sense. If we can have AI that can generate text or images, imitate people's voices or write code, we can also have a lightweight model that can detect ads and skip them during playback. There's a model trained on SponsorBlock data for detecting sponsored segments https://github.com/xenova/sponsorblock-ml
I'm sure that we can have something similar but for embedded ads.

Tailscale has a very neat feature called Tailscale Funnel, which makes this pretty easy