I would use the desuperheater (water assist) to heat a pre-tank before any DHW device/equipment.
The plan is to use a Triangle Tube SME Multi Energy tank that has 100 gallons of primary boiler/hydronic water surrounding a 60 gallon inner tank of domestic hot water. The Geo unit would be tasked with keeping the water in the inner tank at 120 degrees so the outside water should be also at 120 degrees when everything is said and done. Radiant floors would draw from the 100 gallons of primary water and the desuperheater would also temper a preheat buffer tank (mostly for summer benefit as the Geo will be supplying the heat in cold months anyways.).
You can. You do want it simple and less costly and maintenance free, don't you. What would your warranty be after everything is installed??
Am I making this too difficult? Am I chasing that last dollar of savings but adding a lot of cost and potential disappointment? Should I just KISS and put in an instantaneous Hot water heater behind a buffer tank and call it a day? I'm looking for a sanity check here and hoping you guys can set me straight.