BogaMoge I agree with the excellent answers above, Ente and Magic Earth are fantastic....
BUT... I'd just recommend you install GOS plus Sandboxed Play Services and then use it exactly as you use your current phone, including Google Photos and Google Maps, and all settings at default value.
This way I believe you can't get overwhelmed with changes and GOS is protecting your security and privacy already much better by default. And you would see if any issues occur that are directly related to GOS and not any new app.
Get accustomed to the few changes you can see, and all the neatly implemented privacy and security features like Storage Scopes and Network toggle, whenever they present themselves. Read through the feature, usage and FAQ section of the official website over the next few weeks to learn more about all the control and agency you suddenly have.
It will be magic, every day a new discovery. And once you're ready, you'll start making changes according to your threat model (which you should make right away if you haven't already). You might end up using open source only apps, many user profiles, duress pin, pin scrambling and all the other features. But take it one step at a time, I have seen people try too much at once and then go back to Google, Samsung or Apple which is just sad...