ᐅ System diagram including buffer tank and solar thermal system

Hello

I am modifying my heating system. A 1000L (264 gallon) hygienic buffer tank with 6 solar thermal collectors will be added to an existing gas condensing boiler. I have drawn a system diagram and would like to know if you would set it up the same way.
There is an underfloor heating system installed.

Regarding the diagram, I need to explain what I have in mind:

The controller is supposed to measure return flow sensor 1 and buffer sensor 2 and control a 3-way valve. If sensor 1 is colder than sensor 2, the buffer heat is fed into the gas unit. If it is warmer, the buffer is bypassed.

Better to use photovoltaics with an electric heating element than solar thermal systems. ;-)