Since your having trouble with the entire system you should put a gauge on your closest outside hose connection near the (meter) and check the pressure.
Take this pressure and times it by the constant of 2.31 and this should give you an idea how far it will elevate the water.
Then of course you can add the pressure needed at the highest fixture and friction losses.
By finding the main pressure you will have a better understanding of what’s going on.
It could be a crushed lead pipe main Or a ferrous piping system with internal corrosion Or if the pressure is good then you will have check inside the structure for either a partially closed valve Or the piping may have calcium deposits.
You must do one step at a time to find the cause of the problem