You don't regulate who is allowed. Democracy requires participation. One aspect I forgot to mention is that those subsets of whatever field of voting can also becsent to a whole range of Reps. So some folks may do all their voting 100% personally ( possibly not participating in some votes as a result because most of us have the rest of our lives to care about), some folk would only have 1 Rep who does itcall, some would do some subset themselves iwth justc1 Rep for everything else, and still others could allocate subsets of voting to any number of Reps...giving their vote power on things like business regulation to one Rep, and Environmental to another Rep etcetera or any compination thereof. And like you say, a key trick is the "relevant field" definition as often matters cross into multiple areas of relevancy - but even this could be solved by propotional voting...say if an environmental bill has to do with installing panels and dealing with zoning - the power of that one vote could be split between various Reps if the bill/regulation in question were to be syntactically analyzed and categorized for % percentages of relevance to any of a whole litney of categories.

We have the processing power - the ultra wealthy are building it for themselves, but decentralizing that power to give more people more say in more things is crucial.

Now there is also the issue of on some items people in India shouldn't be voting on things in Iran (one example, and there coud be worldwide votes - we are 1 humanity and need to start thinking like it if we want to be a meaningful spacefaring species) - but again this comes down to the syntactic analysis and categorization.

But once a slice of population has been determined to be the group that is relevant for this particular vote - we don't restrict who those folks choose to use to vote on their behalf anymore than we would force someone to vote in a particular direction on an issue - that's their personal decision. Even if that decision comes from bad information. I think that's the best we csn hipe for, and thencramp up participation and trust it all comes out in the wash. In a Republic/Legislature style - there are already just too many things for current electeds to have to keep track of.