That's sound in theory, but app developers don't really test on low end phones, so the apps tend to get more and more bloated as time goes by. As soon as you need something with a map, you're pretty much fucked. Looking at all the hiking maps that just get progressively worse without adding anything that I care for.
Well Jolla phones run Sailfish OS which doesn't support this anyway so probably not the phone you should be buying (And the phone supporting Sailfish OS doesn't suggest at all that it'll be able to run a "regular" Linux distribution either)