Turn off hot water without hot water valve
My approach would be to turn off the water heater and the cold supply.

Then open a hot tap below, or as close to the area of the leak, to drain the hot pipe.

Then be prepared to catch the remaining water when you cut the pipe around the leak.

Supplement:
One can get “ice clamps” that can be used to isolate either side of the leak but can be fun if the water pressure pushes the ice plug out...