How do I enable USB debugging from TWRP After a series of idiotic events on my parts, I have ended up with full software wiped (including stock os) without USB debugging or any roms to flash. I am able to access TWRP but pretty much nothing else. If details on the events are needed to help, I will gladly disclose them. Immense thanks to anyone who attempts to help.
Your concern right now should be to flash a working ROM in your device. That can be done easily using TWRP. Connect the device when booted into Twrp to PC, and the PC would see it in MTP mode. You can then copy flashable files to internal storage from PC. TWRP, in addition, comes with USB Debugging enabled, so you can do sideloading as well.

Alternatively, you may have to rely on some MI flashing tools, but I don't have an idea of how they work.

Regardless, if your OS is wiped out there is no point thinking about enabling USB Debugging there, because it cannot help you flashing a new ROM. ROM is flashed only via recovery or low-level boot environments, such as fastboot. Furthermore, the concept of USB Debugging assumes there exists a functioning OS (recovery or fully-fledged Android) which would receive the debugging commands. There exists no Android OS, so it is futile to think about USB Debugging.