Do they work without an iOS / macos device though?

I've used custom ROMs before, but it's easy enough to hide whatever app you can't remove. Google news for one can be removed and I have from my pixel for attention reasons. The app timers functionality is super useful for any applications you don't want to use more than a few mins a day too.

If you want a non-mystical theory-of-everything for meditation, you can't do much better than Shinzen Young. His article, "What is mindfulness" is a good start and I highly recommend his book "The science of enlightenment"(science being metaphorical here). He had multiple free PDFs of meditation practice manuals on his site and many YouTube videos as well.

While at deeper levels, meditative experiences enter the ineffable territory quickly, Shinzen has done an excellent job defining terms precisely and breaking down things into relatively simple terms. He writes as an engineer/scientist would and in my opinion, brings a much needed clarity to the theory and practice of meditation.