My App sources: I prefer privacy over security and I like to keep as few apps as possible on my phone.
Phone: Third Party F-driod Repositories → IzzyOnDroid → Main F-droid Repository.
Tablet: Accrescent → Third party F-driod Repositories → IzzyOnDroid → Main F-droid Repository → Aurora store.
F-drord’s security has billion posts on this topic.
Accrescent feels too much as a alpha for me and only have 2 apps that I use and both has Third Party F-driod Repositories. I pretty must only uses it on my tablet to follows Accrescent’s development.
Aurora Store vs Sandboxed Play Store idk I only use one closed-source app that need GSM so I prefer Aurora Store’s spoofing over Sandboxed Play Store when I only need one app.
Obtainium to must bloat. 
Maybe someone has a setup you like here.