As water heats it expands. Without a check valve on the incoming cold water, the water heater
will push hot water into the cold water plumbing
. You don't need a big accumulator tank. You could add a vertical pipe or hose capped on the top, on the hot water side. With the pipe mostly full of air, the expansion pushes water up the pipe, and cooling
it goes back down. Mount your pipe somewhere behind cabinetry.
To get better control of cut in and cut out pressure, you'll probably need a separate pressure switch. Lots of pressure switches for sale
on ebay, 12v, 120v, etc. I use 2 switches, one normal 40/60 and another that turns on the pump as soon as a tap is opened, so showers, etc., maintain constant pressure. I switch between the two with a relay controlled from the galley