HERE Maps is amazing. Has great offline map support; you simply download the maps you wish to use. Routing works offline as well.

I think the same, but if your usage is more limited to such apps, maybe a smart watch can get the job done. Using it less instead of getting rid of it sounds good as well.

Aren't current smart watches mostly tiny displays for the phone in your pocket though?

Mostly, but I think Samsung now has one that has its own cellular connectivity (with its own SIM).

Even a smartphone in airplane mode can give you a lot of functionality, especially offline apps like Kiwix and Maps.Me.