Potential solutions include giving everyone the same amount of starting artificial "money", using one-person-one-vote when issues are polarized along wealth-lines, or making votes more expensive for the wealthy.
To me, the first option of delegating everyone the same starting votes seems the most reasonable. However, I think allocating vote prices based on wealth could create some interesting incentives and resulting politics.
This is equivalent to gerrymandering political districts. Spread out the votes on the issues based on the electors in favor of a predtermined outcome.
Of course, this brings a difficult problem on a national scale. Often many seats are run uncontested, even in large areas. So if we had a minimum of 1 vote per candidate, that would give certain areas and certain elections more power. You could then "hack" the election simply by running extra candidates and make it seem more contested. While I like cardinal systems, I think quadratic gets extremely complicated as soon as you try to expand it outside of a localized election and maybe it isn't worth it.