I'm unclear on why F-Droid is any safer than the playstore and not possibly worse since using it tells potential malware purveyors that you're into sideloading in the first place.
By default, F-Droid provides only the applications that they themselves have verified and built from source. They also allow the user to add other sources from other parties who the user trusts (e.g. GuardianProject, IzzyOnDroid, and others[0]).
Google provides any application uploaded by any anonymous third-party who signs up as a developer (and in future, provides the required ID).
It’s not just a random hodgepodge of “third party” binaries. It’s all FOSS software that was actually built from source and verified.
Probably much safer than a random app on the Play Store.