Injection molding

Don't you also need to regulate the temperature via a relay that controls a heating element of some sort?

I guess it really depends on whether the OP is better with computers and software or discrete components.

A comparator and a 555 timer, adjusted by a potentiometer would suffice.

One of these could be useful (though they might just be total worthless garbage, it's hard to tell):
www.aliexpress.com/item/1005006797695369.html
www.aliexpress.com/item/1005007341104525.html

The Linuxcnc-RIO\riocore has a max6675 plugin.

github.com/multigcs/riocore/blob/main/ri...ns/max6675/README.md