Canta

Don't bother, there's still Unihertz's spyware in there. LineageOS and derivatives are buildable as generic images that use the OEM drivers, reported working on that specific device. It's a complete pain to build but some random people publish premade files, see here (get the first "Vanilla EXT4") and here. More options there.

There's a manual specifically for the Unihertz Jelly Star here. Although the download link there is outdated and the MicroG instructions are also outdated (follow the official ones instead).

If you don't want to use the phone, may as well give it to a comrade locally that wants it.

in the US (...) we got rid of 2G

Sad. Although there should be modern bricks with 4G that aren't too expensive, usually marketed as "for grandparents".

There are other phone manufacturers than Nokia. Always have been. Shocking, I know.

EDIT: looked around and the ones with reasonable prices are usually the carrier contract ones from the carrier stores and carrier prepaid ones from literal grocery stores :/

FuriOS

Never heard of it.