If you want control of brew temperature, you will need an independent brew boiler- i.e dual boiler machine.
The nature of HX is that brew water is flash heated in as it moves through a tube (HX) in the boiler. A change of a degree or two in boiler temperature will not have anything like that effect on brew temperature.
In this application, the PID merely acts as a digital pressurestat.
You may wish to consider our Izzo Alex Duetto. It's outstanding and sits between the EVO 2 and R58 on price.