on a tankless feeding a regular tank, it should cost no more to
operate than a regular hot water tank.

the tankless initially heats the water to whatever it can, then sends
the water to a regular tank that does its normal job.

endless hot water regular tank conveniences and the only extra cost is
the line between the tankless and regular tank, ideally it should be
short and well insulated.

true the tank will have normal tank losses.

today i have to stop at home depot and while i am there price some hot
water tanks. just to verify some of these issues