My understanding is that completely de-googling the phone is somewhat hard because of Google Play Services being a prerequisite for many services. I understand that you can get by without it, but many people find that somewhat of a burden.
Usual warning here: microG does talk to Google servers still so it's not really Google free. Way less than Google's version though.
The main missing part is a good maps/Waze equivalent. I don't need anything else that's not available on F-Droid. Now I'm a GNU/Linux user of strict observance (depends only on Free Software!), so I probably don't have the same requirements as most.
Have you tried OsmAnd? (and if you have, what are your thoughts?)
I didn't try it, but what I'll miss the most is traffic information (I live in a very crowded area with huge traffic jams).
WhatsApp works, but you have to check from time to time since Google made Playservices mandatory for push messages. Signal and Telegram don't.