Changing the tax code would be paramount to a constitutional change so make any rates locked in and only changeable by state ratification or more than simple majority in both chambers.
There would also have to be same type of laws for spending and balance budgets mandatory. The states have got to have more say so when these entitlement spending bills come down the pike.
Repealing the 17th would help by putting senators again answerable to the states.
An easier way is for states to halt the Federal Government from taking taxes directly from its citizens. The state would collect those taxes and hold them in escrow. If the Federal Government starts getting uppity, the state simply does not release the tax’s he;d in escrow. THAT would give each state tremendous power and put power back directly into the hands of the people of each state.