Opting not to sign in with a Google account reduces some of the information you’re giving away.
These services also give third-party apps access to some of that functionality.
Using an alternative app store means allowing software outside of the Play Store to be installed, opening yourself up to these kind of attacks.
Unfortunately, this is a trade off you have to ask yourself.
If you choose to go a step further, like I did, and use only open source software, say goodbye to social networks, music streaming services, popular games, most navigation tools, cloud storage providers, video streaming sites, and most productivity tools.
There are alternatives to some of these apps available, but if you want to go 100% open source, you’re going to miss out on quite a bit.
How functional your phone will be out of the box will depend on the manufacturer.