Gregory's Server
Imagine, using your old phone as a Raspberry Pi-like computer.
Or as a Smart TV dongle.
Or flashing simple OS to make a dumb phone and give to your parents, use on camping.
Or just installing lighter version of OS like we have with Linux, instead of one-fit-all like Android.
I had to change my phone 3 times in the last 7 years and feel like my current phone is not going to last much. Meanwhile my computer is still running the same, even having 2x less RAM than phone, the only parts I changed was a fan and disk upgrade.