Coffee machine PID controller

My beloved 1976 La Pavoni Europicolla coffee machine is in need of an upgrade. I’m wanting to add a PID controller to the boiler, and wonder if I’m on the right track. I have an electrician for a father, who is happy to deal with the 240VAC side of things.
Ideally I would like to fit everything in the base of the machine, though if needed I could put it into an external box. ie I would prefer everything to be compact.
I’m thinking of using a RPi Pico for the PID controller, and a screw-in DS 18B20 IC sensor, along with the 40A SSR from Sparkfun.
The machine would have two settings - one full-on for steaming, the other controlled by a PID program on the Pico. I would experiment with different temperatures but probably around 92 deg C is where I’ll end up. I would switch between the two with a 3-way rocker switch. The pico would be powered by a power supply such as this one
Circuit diag 2022_04_06
Am I thinking of the best sensor? Is the Pico the right tool for the job? Any thoughts on waterproofing? Am I right in thinking that I would use a slow PWM for the element (say, 1Hz) to avoid excessive switching?
All constructive comments welcome!

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Hi Andrew

Probably. Another thing to think of. The switching pulses whether on or off should be longer than 10ms as the SSR will probably be a zero crossing switch type and anything shorter than 10ms would not guarantee a switch.
As for the Pico being suitable I am afraid I have no idea at the present.
Cheers Bob

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Hi Andrew,

Looks like you’ve got most of your ducks in a row already, I can say that the Pico is cheap, fast, and very easy to work with in MicroPython.

Seems there is a simple PID library around already, so most of your work is likely already done!