Supporting Android apps to some degree has always been one of the priorities of the postmarketOS project, with Anbox support being one of the oldest issues in the project's bug tracker. The news is, this issue has been very recently marked as solved after two years of work, as Anbox officially landed in its repositories and is already working (at experimental level) on most devices.
While the degree of support will be clearly still far from that of a native Android system for a long while, the good news is that Anbox is not an emulation layer, but rather a containerized Android image with hardware access abstraction, solving most performance bottlenecks.
The project promises full integration of Android apps, to be treated as natively as possible in any Linux system, although several low-level complications (such as custom kernel modules) and the higher than average amount of work made only few of distributions support it entirely so far.
This is not the first time a mobile Linux project focuses on supporting Android applications: Sailfish OS offers a compatibility layer for Android applications, also eased by running on Android-specific "downstream" kernels natively, and Ubuntu Touch also offers experimental support for Anbox.
As the "mobile Linux" app ecosystem is still limited, although rapidly growing, letting users run their favourite Android apps will make a potential switch less painful for sure. And while it is still early to suggest using postmarketOS as "daily driver" on your smartphone, we are getting there surprisingly quickly.