Music… music…

This is such an undefined element that you don’t know how to deal with:

Trackers are labor intensive, but allow a fair amount of control; unfortunately, they conflict with the approach: don’t repeat yourself. Also, they have a problem with pre-tacts.
Sequencers are ok, but unfortunately there isn’t one on the market that I’m used to: the Amiga Music-X. It’s exactly about the ability to define a soundtrack and then be able to run it. There’s a similar feature in SoftSynth, a software synthesizer with a sequencer in the form of a “program” available for the Atari 8-bit computer family.
The note notation is too simple – it doesn’t allow for “craziness”.
The best solution for me would be a sequencer with the possibility of inserting notes manually (from the keyboard), and with the possibility of defining the sequence – but I haven’t found one yet.

The second thing – I had a lot of finished tracks in MIDI format. Unfortunately, although Music-X exports the files to midi, it doesn’t make sense – all the sequences start from the beginning and play once.

Fortunately, I was able to find a solution on how to get them out of Music-X.

Update 2021:

I have found such sequencer – it is the Auxy Studio, unfortunately available only for IOS (which I thankfully have)