The app situation is not perfect, but there are some (not all available on every distribution): https://linmobapps.frama.io.

Specifically Pure Maps is available as a Flatpak and can be used in conjunction with OSM Scout Server for Offline Maps.

Also, Anbox support got almost usable in the PinePhone’s ArchLinuxARM distribution with working networking and a working keyboard just yesterday, so some Android apps are going to work. I expect Manjaro to ship at least the same level of Anbox support with their PinePhone CE.