If you can get a factory rom, usually you can root it with magisk if you can unlock the bootloader, you don’t necessarily need a custom rom, magisk can patch stock roms.

With rooted location mocking, apps can’t see you mock it, maybe pokemon go can, but I tested routing and navigation in organic maps this way.

Nanolx has a very detailed install instructions for microg with edge cases: https://gitlab.com/Nanolx/NanoDroid

If you can root your phone you can install whatever location mocking app from fdroid, they should work in all apps, an some may even work on ancient android versions.

Network based location is available via other ways, not just by the goog, if you install microg or only its location part unifiednlp, you can get quick rough location from celltowers and even crowd sourced wifi based location, formerly collected by mozilla, nowadays by poziton.

Some links for further reading, if you not familiar with android rooting scene,you will have to read a lot:

• https://microg.org/
• https://github.com/microg/UnifiedNlp
• https://positon.xyz/

Some location mocking apps, I used one some time ago, but I don’t remember which one:

• https://f-droid.org/en/packages/cl.coders.faketraveler/
• https://github.com/warren-bank/Android-Mock-Location

Interesting intersection, but what about the combined sidewalk-cyclelane in the distance. Here where I live cyclist hate when the bicycle lane is next to the sidewalk, because pedestrians accidentally wander to the cycleway frequently. They prefer when the cycleway is next to the road instead.