I find F-Droid more trustworthy than the Google Play Store because the F-Droid maintainers are much more transparent and communicative than Google is. The Play Store review process doesn't do a thorough job of checking apps for privacy or security issues and doesn't require apps to disclose anything other than their permissions. F-Droid reviews every app before accepting it into the main repository, and labels apps with tracking or other potential issues with "Anti-Features" labels.[1]

Any user can inspect the source code of any app in F-Droid, while that's not even an option for proprietary apps in the Play Store. When someone notices an issue and reports it to F-Droid, the maintainers listen and either change or remove the app listing, with these removals being logged in their weekly updates.[2] For Google Play apps with issues that you happen to notice despite most of the apps being closed source, unless they get media coverage, you'd be lucky to get anything other than canned responses from Google when you report them.

F-Droid also has some great apps that depend on sensitive permissions that are forbidden by Google Play, such as the AdAway[3] ad blocker which uses either the Android VPN interface or system hosts file. AdAway enhances user privacy and security by blocking trackers and malware hosts, so Google did not improve Android by removing AdAway from the Play Store.

[1] Anti-Features on F-Droid: https://f-droid.org/docs/Anti-Features/

[2] F-Droid weekly updates: https://f-droid.org/en/news/

[3] AdAway: https://f-droid.org/packages/org.adaway/