@ALL who are involved with testing different memory fix drivers and such, have you guys messed with above 4g decoding at all? I just realized that setting is enabled in my UEFI firmware (I can't remember why I enabled it, but it is enabled, I know by default it is disabled). Another thing I just realized about my UEFI config, I disabled the second ethernet adapter (the i211), mainly because I'm not use it at this location, the i219 is good enough for what I need...
I'm only mentioning these because they may perhaps play a role in getting all this working? Perhaps disabling certain features may allow more memory to be freed for the macOS kernel space, resulting in successful boots each time.
I just now tested booting using f12 menu, booting directly into Windows (7 and 10), macOS still working. IGPU has been enabled, CSM was disabled (will try later with it enabled), no WIFI card installed, still on F7 BIOS (will update to F8 some time later today). But as mentioned above, above 4g is enabled, and the second ethernet adapter disabled. Maybe we all have to find some sort of tradeoffs in enabling/disabling certain things to make enough room for kernel space? I mainly got this board because it was at a good price, less than what I would pay for a Z390 Aorus Pro and a separate TB3 card lol.