I installed Bullseye on a test Pi4. Graphs1090 would not install because Python2 is missing. Bullseye comes with Python3. A temporary fix is to install Python2 over the top of Python3.
Modified the install script … let’s see if that helps.
Well you already had the python installed so … not really a test.
Anyhow i’d expect it to work.
It’s a bit complicated because in the version after bullseye collectd uses python3 …
But it’s not a package dependency because the python plugin doesn’t have to be used.