This is a really good collection of articles about what is spyware and what not. Click on the articles section and you will get a list about programs and then it will be evaluated by strict rules if it is spyware or not.
Most articles are on internet browsers, so this is helpful if you want to chose an internet browser to use, since let me spoil it for you, most browsers are spyware. If you want to pick a browser quickly, you can view the results here: https://spyware.neocities.org/articles/browsers.html so ideally you only want to use one of the top tier privacy obviously. Otherwise for a direct guide I recommend DigDeeper which I also linked: https://duion.com/links/dig-deeper
There are also articles on other programs and platforms like social media, messaging clients, search engines, video games, media players and misc software. It is still interesting to read some of the articles even if you are not using that specific program, to understand what the problems in software are about and of course you should not use any program that has spyware level "extremely high" if possible to maintain your sanity.