The solution has always and will always be to respect the laws of thermodynamics and rising entry.
Demurrage [0]
Consider the following: You have a zero lower bound constraint on the interest rate in your economy. The real interest rate falls below zero. What happens? Deflation. Deflation ends up forcing the real interest rate into the positive range even when the nominal equilibrium interest rate would be negative to reach a real interest rate of zero. So in the deflation case, equilibrium simply doesn't happen.
If equilibrium is not possible below zero, then the currency must be operated in the positive interest range. Hence you need eternal inflation to force the interest rates back into positive nominal territory. Since positive nominal interest is still a net inflow of money from consumers (interest is priced into consumer prices) to money holders, the end result is that money flows to those who already have money and way from those who need to fulfill their basic thermodynamic maintenance even in the case where the real interest rate is 0%. Turns out lying about thermodynamics doesn't work in the end, so you get the worst of both worlds: inflation and inequality.
Another way to conceptualize it is that cash is a guaranteed 0% bond and the real interest rate can be negative due to thermodynamics. The government is obligated to pay the difference between the 0% interest rate on money and the real interest rate in the physical economy. It's like the savings that should normally be effected by thermodynamics turn out to be financial garbage and the government obligated itself to buy off the garbage. Of course what happens is that more people produce financial garbage in response to the government's minimum price floor. Eternally rising government debt is a foregone conclusion and it has nothing to do with political incompetence (ok not introducing demurrage or abolishing the ZLB is a form of incompetence, but its a binary matter of doing it).
If you want debt loads to shrink, then borrowers need a form of leverage to reduce the durations of debts. If the contract says the debt must grow over time and holders of money have no duration restriction on their holdings then you would have to be stupid to not expect this output. Note again, its the duration of the positive balances being decoupled from their negative counterpart. The interest payments are just a side effect that accelerates the problem.
Oh and those who obsess over non-money financial assets: Money is a utility and a monopoly. Capital markets have various types/forms of formal agreements based on contracts. People with money would never accept conditions that are worse than the conditions on money, so in the end the capital contracts are just mirroring properties of the money that the original investor is handing over. Debt contracts have fixed terms and payment schedules and liquidation preference/rights upon bankruptcy, whereas most investments do not have that, which is why a risk premium is added on top. An economy without ZLB money but conventional capital market contracts are mostly be fine since thermodynamics/reality are reflected through failure of the investment.
[0] https://en.wikipedia.org/wiki/Demurrage_currency