Suggestions on DIY water temp sensors to mimic Aquanta water heater

So the Aquanta water heater device is pretty much just 2 sensors attached to your hot and cold pipes. They connect to the main unit which then determines when the send power to the water heater and when to cut it.

Well it doesnt integrate with HA nicely. I can cut/allow power to the water heater via a Shelly. I can write my own logic through HA as to when to allow power or not to allow it, etc.

I’m just trying to figure out a solution for the sensors. Does anyone have suggestions? Im open to using ESPHome or whatever I would need that would allow the sensor to talk to HA.

Below are pictures of the sensors.
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They don’t look very sophisticated, You could probably just use a Dallas sensor.
But not sure about the accuracy and all that. But that can probably be corrected in software.
I would try with the Dallas sensors that is not on a cable, they are smaller and if I recall correctly they have a flat area which should make them easier to “mount”.