My MacBook M2 keyboard was dead. How did these keys revive it?

After a recent repair my MacBook Air M2 was working good as new. I used it 5 hours and shut it down. The next day after start up the keyboard was unresponsive. Touch pad was okay but no key worked. A restart and a power button restart did not help. I read about the SMC reset for older Macs not knowing the M2 does not have System Management Control. I pressed Shift + Control + Option + Power Button. The M2 started and the keyboard was still dead. I pushed the same key combination with power on. The M2 restarted **and the keyboard functioned again.** I understand those key presses are for DFU mode. I had no second Mac connected to the M2 with dead keys so no DFU action was taken. The M2 had gone bad after a glass of wine was spilled upon it. A local non-Apple authorized fix it shop replaced two capacitors and cleaned the circuit board and keyboard with isopropyl. I'm typing right now on the M2 that was broken, fixed, then lost its keyboard, then got its keyboard back by the key presses mentioned above. *Does anyone have an idea of what happened here? How could pressing DFU mode keys with no second Mac connected revive a dead keyboard?* I have bought an M4 since the keyboard quit on the M2 after the repair. I am thinking something else may also go bad on it at any time, but maybe not. It would be nice to have the $900 back for the M4 if this repaired M2 is good to go. Is there a keypress that will test the Mac M2 system for functionality and tell me if this repaired computer has an unseen issue?