Several instruments in one track

I get too many tracks in my projects just because when I create a track for an instrument which just plays on a limited part of the timeline, let’s say as an example the beginning, I no more can use this track later.
So project are very complicated in their dozen of tracks and layers.
I would hope that when I create a bass track, I could put into this bass line the first bass using one instrument, and later change to another instrument, and again and again… just as musicians do…

Best

If you are you using the same VST instrument for these you can use different channels. Is that the case?

Different VSTs, for exemple Halion 6 and last Arturia’s Pigments.