lcalamar this is a very good list.
Browsing for Foss apps is a really hard task, most Foss projects just suck, small personal projects that don't really get traction, are half development and/or abandoned. And app requests in places like r/fossdroid will result in several answers, no reasoning and you'll still be left to try out 5 or 6 alternatives for each app.
privacyguides.org/en/tools is perhaps the best place to find app suggestions.
- There may be no good Foss alternatives for some services.
OSM works relatively well in the US, but is completely useless in other countries. I use Waze for navigation when absolutely needed, but most of the time I use a Google Maps webapp (which doesn't have navigation). Waze is bad at offline maps, and Gmaps requires an account to download them, so I have organic maps lying around just in case. Even in the US, if you're in a big city there's no real alternative to using Waze/Gmaps to get directions that take traffic into consideration.
As for keyboard, the stock keyboard is as good as any Foss alternatives. Gboard is the best alternative if you want dictation (there are tricks to make it work offline, though, lmk if you're interested), but SwiftKey is definitely the best keyboard. Just turn network off after downloading all languages you'll ever possibly want, because you should never turn it on again.
- Lastly, I want to emphasize the suggestion to use webapps and avoid apps. It's a good idea to use different browsers for logged accounts and general browsing. I suggest Vanadium and Brave/Mulch respectively. As bad as they may be privacy-wise, it's always better than using actual apps.
PS: Firefox-based browsers offer better privacy, specially hardened versions, but the safety issues make them bad choices to use in Android.
PPS: Vanadium and Mulch don't have native content blocking, but you can set up a blocking DNS in settings > network > private DNS.