This can be easily, although it takes some work to do, to compile for a RPi, on a RPi. I was able to do it on my RPi3 running Bullseye. You can do it using the Debian/Ubuntu compiling instructions over on the Github. (I found that when it came to the "make" command, just using "make" without the "-j$(nproc)" worked best since the Pi3 is kinda slow, it may work fine on a Pi4.)

Where it gets time consuming, is that you need to install the dependencies. Taglib 1.12 (which is highly recommended because 1.11 can corrupt .ogg files) needs to be compiled from source (unless the Pi repository has finally been updated), same with Qt6 (Compiling Qt6 was probably the most frustrating part of the process and it takes a while to compile it on a RPi3. Qt5 can be added through RPi's built-in software install app). What I did was run "cmake .." from the "build" directory and watched the screen output to see what dependencies were missing and added them. It can be frustrating figuring out what the name of the dependency is when trying to add it from the Pi Repositories. The official software installation app is a big help with eeking out most dependencies, "apt list" is another big help, some I just had to resort to googling to find the dependency name.

Yes, it'd be nice if someone would add it to the official repository, but once you have all the dependencies installed it goes fairly quickly. Obviously, the downside is that you have to keep the dependencies installed so that you can compile newer releases, which takes up space.

I don't frequent here, but if you want some assistance and are patient, I might be able to help if you hit a roadblock. I'm not a programmer or a heavy Linux user, so I can't really answer compiling questions outside of those issues I ran into compiling this and other software on my Pi, but I can try to answer any questions you may have.

Edit to add: I went through all of this to compile version 1.0.2, compiling 1.0.3 went very smoothly since I had all the dependencies installed when I was trying to compile 1.0.2. Just to let you know that the latest version can be compiled and run on a Pi. The verison of Bullseye I am running is the 32 bit version.