To start by poorly quoting Jack Ma: "I always look where the money ends up"
To sort out government finances we should start by simply looking at that: Whereto all of the monies goes?
Usury laws have of course long been abolished in the cleptocratic corporate theocracies of the world.
Most important: Rent/mortgage and Energy. Food is still remarkably cheap because our owners didn't want farmers ruling the world. Farmers are much to advanced at looking far ahead in time. In an equal game vs the corporate quarterly reports they would pwn the unwashed managerialists.
Rent is of course the worse! In countries and cities that escaped carpet bombardments houses may be many hundreds of years old with renters endlessly paying for the "privilege" of living in a house in a country that is claimed to be theirs.
Sure, we periodically put some new wood, bits of plastic and bits of metal into the buildings, renovations that costs a shit load of money. Not that construction workers earn that much but they some how miraculously cost a shit load.
We should really turn rent into a lease-buy contract retroactively. Those few people riding along on the gravy train that is YOUR labor should really not be entitled to enjoy endless exploitation. Investments should have reasonable returns and come with reasonable risk. We've zeroed out the risk for much to long (to the point of people paying rent for flooded houses) that it is perfectly fair to now max out the risk and have the people who paid to live in the house take ownership of that what they paid for. I don't consider this an invention tho, it is just obvious.
The first invention is to create government mortgages at zero percent interest with no obligation to pay anything back until the house is sold with a maximum of 300 000 Euro or Dollar. Furthermore, these financial instruments granted to the citizen may not be sold to other parties until the entity holding them goes into bankruptcy , until that time they are simply part of their balance sheet. The only thing the citizen pays for is a bit of insurance, some 10 to 30 bucks per month and any borrowed amount beyond 300 k.
The second invention is what I call TAX MONEY. This newly coined coin is issued by government every 6 months and they expire after 12 months. Government uses this coin to pay its employees and to buy services in the public sector. Citizens may use this coin to pay taxes over the 12 month period OR they may pay 200% taxes using the normal currency. This creates a highly speculative investment vehicle with varying supply and demand. Government spending may cause radical inflation and deflation, the currency may implode or grow close to 200% of its initial value.
Taxes are paid at a fixed ratio where 1 coin is 1 unit of the normal currency. If you make a purchase worth 100 Euro and have to pay 20 Euro worth of tax on top of that you can pay 20 tax Euro or 40 normal Euro. If the exchange rate is 10:9 you can of course conveniently use your phone to buy 20 tax Euro for 18 Euro on a private or government currency exchange.
Besides the above described weirdness of the system it creates the totally weird situation where we want government to spend enough tax money to drive down the value of the currency. Government overspending makes the currency crash rendering a few months worth of tax free shopping. A few (or many) speculators will probably get stuck with unspent taxes but that is simply the risk of their game. Others might wait until the very last moment to pay their taxes waiting for favorable rates. If that doesn't happen they end up paying 200%.
Government pensions and other kinds of social support (like a basic income) are paid in tax money but the amounts are in normal currency. If tax Euroes are worth 50 cents and the social support is 1000 euro you get 2000 euro.
However, (to make it all work) all monthly payments in the country (where possible) shall be paid per day.
in stead of working a day then having to wait up to 3 months for that day worth of salary to be paid it shall be credited before the end of the day (24:00) If for whatever reason the salary is not paid the same day government will credit the missing money and the entrepreneur will pay 1% interest per day. This money will be hoarded into an account to pay for all those missing salaries. You can still pay 90 days later, you just have to pay roughly twice as much.
Now I understand this is all very hard to grasp for many readers (as if I have many readers HA!) but I assure you it removes tons of complexity from both civilian and government finances, it completely gets rid of a good number of awful risks and it brings a ton of fresh money into circulation without the risks normally associated with governments "over" spending.
Without housing cost people will have much more money in their pocket and the tax system is such that it dynamically adjusts to whatever weird things unleashed onto the country.
If there is a billion or two needed for some disaster management the money is instantly available AND TAXES GO DOWN so that people have some extra money to figure out what to make of the situation themselves.
The only down side is that during high government spending saving up your social support (or your basic income) might be a terrible idea. Then again, if government is cheap and efficient you might hold onto it for as long as possible.
All the ups and downs make for a wonderful landscape for speculation and by that process much of the national risk is delegated to the speculators. As long as the financial game is limited to registered citizens the winnings will simply be returned into the national economy.