Would like to set progress for display, based on combination of triggers. Not use only the first active trigger.

I.e. two triggers with progress and return minimum value - compare gcd vs cast, compare first DK rune with second DK rune
or make progress shorter based on subtract of two triggers - debuff on malygos lasts for 10s, but there is some projectile time, calculated in other triggers, that would shorten progress and give easier to see bar

I would like to be able to code it, but even simple choose (same as icon) would help, so my triggers does not need to be ordered in specific way.

Those are all best handled via custom code, namely a watching trigger.