Just thought I'd link up the product I used to drastically quieten my Espresso machine (Lelit PL60T V2)
Self adhesive, Butyl rubber/ Aluminium product from Jaycar.
It has a working temperature of up to 110'C
Butyl Based Sound Deadening Material - Jaycar Electronics

I simply attached pieces of it to the interior of each panel of the machine
It works by adding mass to the case and the butyl material dampens any resonance in the sheet-metal.

$30 well spent for an extremely quiet machine.