The data is based on osm, but a lot of it is removed to reduce map download size. Traffic lights appear to still be there tho. There is already the "routing options" menu where you can set "avoid unpaved roads" for example, so it seems like the routing algorithm they use already supports conditions like this.
Did you check the old (organicmaps) and new git repositories for existing issues about this? That might answer your last question.
The repo for comaps is linked in the community description.
The overall project: https://codeberg.org/comaps
The app: https://codeberg.org/comaps/comaps
It says there that they accept code contributions.