And even a 7$/ku MCU is complete overkill (assuming that's the real price, not shortage-related, though its lead time is over a year, so the price is probably inflated), because literally any microcontroller with an ADC can easily do this. Around ten years ago I built my own on a tiny AVR, and even that would be an expensive option compared to what you could use instead in a commercial product (<0.5 $/ku ARM MCUs).

I haven't had a fan controller for many years though, because they're quite pointless if you do things right.

CY8C32xxx processors are based around the 8051 but they're actually part of the fairly capable Cypress PSoC 3 line[1]. The PSoC 3 includes an 8501 compatible processor along with a bunch of mixed signal peripherals and a PLD fabric to connect it all.

[1] https://www.cypress.com/products/psoc-3

Still overkill. A 555IC, a variable resistor, a thermistor and a few passives is all you need. You could get the BOM for the whole #! down to under a buck.