2- 0.8 ohm
This is not good. Very little.
I read one topic on a Russian site. Many users had a problem with a soldering station, where the 3.3 voltage regulator is made like yours. I'm sorry, but the STM32 chip itself failed.
If possible, unsolder the controller. If the resistance increases, then the STM.
Moreover, they wrote on that forum that the stabilizer microcircuit was also out of order.
Most likely, at first it failed, and then 24 volts entered the STM.
To make the circuit more reliable, the step down converter must be set to 5 volts, and after it, set 1117 to 3.3V