Similarly (easier but less drastic) I’ve seen people turn their phone to grayscale mode to make the device less engaging and remind you that it’s a productivity device, not an entertainment device. On iOS you can do this through the Accessibility settings. (Settings > Display & Text Size > Color Filters > Color Filters on, Grayscale
I would give a try to an e-ink based smartphone if there was a good one. The only reason I got a smartphone in the first place in 2020 was access to maps/taxi/banking apps which would work with any display. But given the grayscale experience I wonder if you get used to laggy e-ink videos as well.