This depends on the PIO in the RP2040/RP2350. As far as I know, that is an innovation exclusive to the Raspberry Pi company, so it would not be possible to do this on another microcontroller:
https://magazine.raspberrypi.com/articles/what-is-programmab...
The microcontroller has additional cores called state machines in the PIOs that are specifically designed for bit banging and have their own custom ISA that reportedly only has 9 instructions.
Yes, it does, although it's almost like horizontal microcode; it can do several things in a clock cycle other than the instruction itself. I didn't mean to imply that you could bitbang 100BaseT with a Padauk PFS150 or a PY32.
The Padauk FPPA chips are probably a bit better at bitbanging strange protocols than any ARM, but not in the same class as the Pi's PIO.