Make a proposal that will be accepted or rejected using consent (all members find the proposal to be good enough, regardless of whether everyone loves it).
Run a dot vote (Each participants receives n dots, which they can assign to m ideas, where multiple dots can point to the same idea).
Run a slider vote (participants allocate points from, say, 1-100 for each of n items, where 100 quantifies very desirable and 1 quantifies low desirability).
It would be interesting to know how loomio manages the ammount of dots. Are there groups of different proposals for one main topic ?
With the voting plugin a user is able to issue n votes in total on the whole discourse, IIRC.
In general, if you need any fancier poll system it’s easier to use a tool that is dedicated to it, like Typeform or Google Form support in Onebox? and embed it into a topic.
Discourse can be very much used for “decision” as stated in the title, but the type of decision we focus is one achieved after all the involved parts dish it our using paragraphs, and a consensus can then be constructed.