YUNOHost iso is basically just Debian, but the one-click-install for various self-hosted things is it’s primary purpose. All done through web interface.

Make an app that guides users when folding the phone

Supposedly Google would have better time taking care of just one consumer OS instead of two, so Android is getting some PC features so that it will be able to replace ChromeOS in the future.

indirectly forces you to buy wireless earphones

USB-C wired headphones exist

edit: lol, replied too quickly. You mention wired headphones in the next sentence.

I think that the insistance on headphone jack has gone too far.
There are now enough wired USB-C headphones and wireless earbuds available.
Yes, there are edge cases, like people who work in audio industry where most equipment uses jack as standard connector, or car aux ports, etc.
But when it comes to most casual listening, there are enough solutions.

When migrating to the new phone I tried with USB-C to 3.5 adapter. It did not work most of the time. I suspect that the issue was in my somewhat defective headphones, which have damaged wire and therefore unreliable connection.
Previous phone and other devices were probably able to mitigate the occasional “disconnect”, while the adapter completely dropped connection.

But then I bought USB-C headphones, which work fine.

LineageOS 22.1 on FairPhone 4

there is a bridge, but some parts of the fediverse got very mad about it
https://github.com/snarfed/bridgy-fed/
https://fed.brid.gy/

GotHub seems to display basic GitHub stuff decently well.
https://gh.whateveritworks.org/

so this is similar to LibRedirect?
https://github.com/libredirect/browser_extension
https://libredirect.github.io/
check out this list of privacy frontends and see if you can implement any of them in Predirect

Also, I see that you only handle one instance for redirect. Either the default instance or custom instance.
Consider implementing multiple instances. Here is list of instances that LibRedirect uses:
https://raw.githubusercontent.com/libredirect/instances/main/data.json
Here is a list of instances that Farside.link uses:
https://raw.githubusercontent.com/benbusby/farside/master/services-full.json

Both LibRedirect and Farside still have to deal with the rate-limiting problem with Youtube and Reddit and I assume other sites as well. Invidious instance or Teddit instance can be rate-limited, resulting in video not playing or post not showing up.
If your extension does not distribute user traffic across multiple instances, then I assume that your chosen instances will get hammered into ratelimit even faster than other instances.
So consider thinking about solution for this.
One of suggestions that I like is to allow user to provide an URL to a list of instances.
That way, someone or some automated system can periodically compose a list of instances and users can “subscribe” to that list.

Also some useful links:
https://github.com/digitalblossom/alternative-frontends
https://github.com/pluja/awesome-privacy#social-networks-and-platforms
https://github.com/mendel5/alternative-front-ends
https://matrix.to/#/#alternative-frontends:tchncs.de

this is a awesome trick that more people should know about

there is also solution for the opposite problem, when you have two machines and you have no idea what is in between them:
https://github.com/magic-wormhole/magic-wormhole
initiating transfer is as easy as copy-pasting or re-typing a short phrase
and it will find the best path to transfer files. If they are on same network, it will transfer locally. If they are on the opposite sides of the internet, transfer will go through proxy server, etc.