[Giovanni LiCalsi]

I'm a retired plumbing contractor.
The best solution is to buy a hot water circulator pump kit for an under sink installation.
The kit has, of course, a circulator pump, check valve, thermostat, sensor and 2 double-port anglestops. The extra ports on the valves will supply water to the sink valve. The kit can be installed on the bathroom or kitchen sink, usually the farthest sink from the water heater.
All you need to do is to plumb the water flex lines into the hot and cold water lines under the sink and plug the 110volt circulator into an electrical outlet.
The circulator pump will be located in between the hot and cold anglestop valves with the pump flow direction pointed towards the cold water anglestop valve.
It simply circulates hot water from the hot water anglestop to the cold water anglestop until the temperature sensor detects hot water, then the thermostat shuts off the pump.
This is simple and cost effective. Easy DIY project.