Thanks for the links, something I have not really thought about. I pretty much assume very low security/privacy on all modern smartphones anyway(commercial or FLOSS ecosystems).
F-Droid is a handy way to find and support devs who are sharing their expertise.
Certainly, use the download-channels that you are comfortable with.
As mentioned on that page, F-Droid and IzzyOnDroid can link you to many decent FLOSS apps. It’s an easy way to be exposed to a large amount of free software.
Winamp Skins Collection link
( * Has some NSFW skins mixed in.)