You are right! MIDI files I'm trying to use are made in that unconvential way, however I checked and that's due to how I get them. Other DAWS I used before import them rigth anyway, so I have never digged deeper on how MIDI works. Now the subject is clear and I have already figured out how to properly get MIDI in a way that they are opened correctly. The issue was that they didn't have information about tracks, only about channels.
Thanks anyone for helping! I would never come to a solution otherwise. It seems to be an amazing and supporting community