The shareholders basically tried to enshittify it

https://itsfoss.com/news/organic-maps-fork-comaps/

Basically concerns from contributors about the governance structure of the project and how their drive for profit may impact it. And how this FOSS project with significant community contributions has it's shareholders (yes it has shareholders) considering it their sole property.

There's a little on Wikipedia here.

And an open letter: https://openletter.earth/open-letter-to-organic-maps-shareholders-a0bf770c

The community believed their voice weren't being heard by the shareholders, and the lack of a good response by Organic Maps led to a fork of the project being formed. CoMaps was meant to have more transparent governance and take more into account community feedback, and both the name and logo was voted by community members! I also know that iodeOS, a French based private degoogled Android ROM, ships with CoMaps as its default mapping app!

Additionally, CoMaps has already had a few neat extra features over Organic Maps added, like a nicer UI, which is pretty cool. And I think the (community voted) logo design looks nicer than that of Organic Maps, but that's just my opinion.

I much prefer using OpenStreetMap apps like CoMaps since you can download offline versions of the map!