Spending OPM is so easy

Singapore would be spending more than $2b to upgrade the fleet of F16s
in service now. With better avionics and weapons system, would the
upgraded F16s be good enough to stand in for the trouble stricken F35s
until they are proven to be as good as they are made out to be? Or would
this $2b plus be on top of the several billions earmarked for the f35s?
It would definitely be a nice fit to