I found myself in a similar situation and also started de-googling, which is much nicer and liberating than I was fearing.

I did the exact same thing with Immich (what a great software, by the way!).

And in case it helps:

Instead of always relying on google maps, I now mostly use CoMaps (https://www.comaps.app/). Way better than using directly OpenStreetMap. And for my Pixel 7, I switched to LineageOS with gapps (https://lineageos.org/) and I'm not missing anything and am very happy with it.

Also, I'm trying now Nextcloud (https://nextcloud.com/), with a setup similar to Immich, and now I do believe there is life beyond google, and it's a better life.