In order to protect your privacy even more efficiently, you need to do something very simple whenever using an online service or a software. Something that most people fail to do is reading the terms of service, also known as a TOS, from companies or developers’ software. This usually will tell you straight up whether they’re spying on you, selling your data, or using it to sell ads. This will solve a lot of problems with people not realizing that some software is actually the opposite of privacy, but they keep using it thinking it enhances their privacy.
If like me you are both lazy and not a lawyer, check ToS;DR https://tosdr.org/ but honestly it’s like labels on food products.
You don’t need the damn label to know that Coca Cola is not good but water is… so yes, don’t use Facebook, great. You knew that already if you care just a bit about privacy.
Still, if you want to go there, please do check https://tosdr.org/ and if you can contribute back.
What I personally find more useful is F-Droid because if an app is not present on it, it’s rarely because technically it can’t, it’s often because of anti-patterns. The app tries to go on F-Droid only to realize it’s not “just” another store but they have rules, good rules IMHO, like no Google Analytics and whatever backends to track user behavior.
Also Android app analysis like https://exodus-privacy.eu.org/ is quite good, same idea, finding anti-patterns but not in code (which isn’t a good start if it’s not FOSS anyway) but rather in how the app actually behaves.
TL;DR: yes, do read the ToS if you can, but if you can’t don’t just press “yes” or avoid and move on, rely on the work of others like ToS;DR, F-Droid or exodus-privacy!