We have a recirculating hot water loop on a timer and enjoy having hot water almost instantly. It’s not quite hot right from the go, because the water in the pipe between the loop and the tap isn’t hot, but that’s what, 2-3 seconds of flow? The timer is set to circulate from about 7am to 10am, then again from 6pm to about 11pm. It came with the house and we’re very happy with it.
My mom’s house is a rancher that has two bathrooms at one end, and the kitchen, laundry, and a half bath at the other. The water heater is in the laundry room. The pipes have a long LONG run through a concrete slab, so it takes a long time for the water in the master and hall bath to get warm, and my dad set the water heater temperature so high in an attempt to compensate that the water coming out of the kitchen tap is probably dangerously (as in scalding temp) hot. (My mom is used to it and won’t let me turn down the water heater.) Dad thought about putting a small water heater in the hall bath cabinetry, perhaps just 10 gallons or so, plumbing it inline with the hot water line. His thought was that they’d have hot water pretty quickly to the master and hall bath from the small water heater, and by the time that tank was out of hot water, the draw from the main water heater at the other end of the house would be hot enough, but he never got around to it. I suggested a tankless heater instead of a small heater, but he was so disappointed in the tankless heater he experienced in NINETEEN SEVENTY-ONE that 40 years later, he refused to believe the tech had gotten better.
When my brother and his wife did their remodel, they went tankless, but the way their house is designed, there are short runs from the water heater to every outlet, so it didn’t matter. ISTR he loved the tankless, both for efficiency and for never running out of hot water (his step-daughter and his wife loved long, hot showers).
No answers, but food for thought. I guess before I could recommend anything in particular, I’d want to know more about the layout of the house.
(edited TWICE to correct typos)