According to this, a build script can be used to set up fresh Raspberry Pi OS Lite 64bit to become a fresh, compiled from source, Stratux. That is appealing for many reasons, one of which is that I might be able to add functionality like supporting different GPS baudrates and modules. One can have dreams!

The first hurdle is to find the Raspberry Pi OS Lite 64 Bit version of the older Buster. It's here. Download the file called: 

2021-05-07-raspios-buster-arm64-lite.zip

2021-05-07-raspios-buster-arm64-lite.zip

I installed that using Raspberry Pi Image Writer.

Unfortunately, the documentation is currently already confusing. At the top of the page it simply states "fresh 64bit RasPiOS Lite Image", further down then "latest 64bit RasPiOS Lite Image" and then a little later: "please use these scripts with caution and only on a fresh Raspbian Buster Image"

¯\(°_o)/¯

It is things like these... ༼つಠ益ಠ༽つ ─=≡ΣO))

Following the rest of the instructions yields a running script. It's currently installing all the dependencies. Let's see how this goes.