The government is a bad capital allocator. This is clear to anyone who has devoted even a cursory look to how the governments of the world, both efficient like Singapore and inefficient like the EU, have distributed their tax and printed dollars. Because the state is beyond any doubt a very inefficient capital allocator, it should be constrained to doing only the obvious things.
Obvious things are those that are by no means controversial or divise among the general population of a given country. Defense is one such thing - a country is, among other things, defined by its land and people, and it should therefore defend its people and its land against capture, death and destruction. Law and order is another obvious choice - generally you want to enforce the rule that it's not ok for a person to kill another person, except under very specific circumstances. Forbidding theft is another candidate likely to be supported by the majority of able-minded individuals within a country's borders.
A good obvious thing should not only be uncontroversial and clearly logical, it should also be extremely simple to measure. The prevalence of theft and murder is very easy to track using digital technology. It's an append-only spreadsheet with zk-enabled privacy-preserving statistics. A country's defense is also easily measurable by the presence of hostile foreign forces within that country's borders, or land captured and held by another nation.
Because obvious things are easy to measure, they are also easy to enforce. When government officials take some amount of money to enforce laws, and those laws are measurably not enforced, the people can dispose of such government officials, and pay new ones to do a better job. This enables competition among providers of government, a feature painfully absent from our current political scheme.
A simple way to enforce the government only do the obvious things is to require a supermajority to agree on those things. If 70%, or even 80% of the voters agree on something, it's much more likely to be essential to their continued flourishing.
To implement the obvious government in an existing city, county, state or union, start by declaring all laws apart from the constitutionally guaranteed freedoms to expire 1 year starting today. Then, require a supermajority to pass new laws, or keep existing ones. Observe how fast the truly important laws and regulations are separated from the useless and harmful.