So this project took a bit more than it should.... After a few tests, I realised that to strengthen multi-color one, I have to add some intermediate layer, as the problem was with connection between differently colored regions. I thought that I just change filament at some layer. However it is not working when I have more than two filaments. I tried a height range coloring function but it coloured only edges... Quite interesting(and frustrating ;)) if you know why is that please let me know.