About to switch to a more privacy focused phone. I’ve never heard of obtanium.
Is it easy to get all the apps with just these two locations?
Discussion
Obtainium takes a bit to learn, mostly about what URLs will be understood as a source.
GitHub and GitLab repos with releases will work, for example with Amethyst:
https://github.com/vitorpamplona/amethyst
You can use F-Driod URLs:
https://f-droid.org/packages/com.termux
And then others like Signal with just:
There isn't a directory to search for apps with Obtainium. So it is necessary to use search engines, repositories like F-Driod and etc to find apps.
You can install from pretty much anywhere, except Google Play (it requires a login, not sure how Aurora Store does it).
The GrapheneOS App Store is used only for the apps that come with the OS and other system updates.