What would be sensible strategies/weapons for a middle-ranking
country to employ if it thought it is likely to be involved in a war
against the USA or other Western countries, say in the next 10
years?

For the peer competitor,even more accelerated downsizing classical military
power and even more accelerated development of HPM weapons.
For others, more attack platforms guided by Mk.I eyeballs and armed with box
cutters.