@sinbad21 Time Machine is working perfectly for me with both Enabled. No problems. I am finding that Monterey 12.6.6 has no problems (for me).
@Ausdauersportler I could have sworn that I wasn't receiving any permission prompts (e.g., Microphone, Camera) in Monterey with AMFI disabled on my dMBP6,2. I am certain that I wasn't receiving any permission prompts in Ventura versions prior to 13.3. I am now receiving permission prompts in Ventura (tested 13.2.1 and 13.4).
The most important development for me, regardless of whether AMFI/Library Validation makes a difference, is that I can use a single EFI to multi-boot Monterey and Ventura. An "in-place" upgrade of Big Sur to OCLP 0.6.7Beta2 did NOT work for me, so I'm figuring that out now.
My dMBP6,2 is a hackintosh, so there is the possibility that my observed behavior is slightly different from that observed on a real MBP6,2 (although I don't know why AMFI and Library Valildation behavior would be different between the two). Maybe because my dMBP6,2 has only NVidia Tesla graphics (no Intel HD).
EDIT: I was unable to boot BigSur 11.7.7 with AMFI and Library Validation enabled (and injecting AMFIPass.kext) after previously installing BS with AMFI and Library Validation disabled and patched with OCLP 0.6.6 (boot resulted in AppleAHCIDiskDriver kernel panic). However, I was able to perform a clean installation of BS 11.7.7 with AMFI and LV enabled (including data/app/system migration from my old BS volume). After the successful install, I applied post-install patches to BS with OCLP 0.6.7Beta2.
I am now booting BS 11.7.7, Monterey 12.6.6, Ventura 13.2.1 and Ventura 13.4 with AMFI and LV enabled and AMFIPass.kext injected and post-install patches applied with OCLP 0.6.7Beta2. All working very well.
EDIT: DhinaK set me straight on Discord. She suggested installing OCLP0.6.7 Beta2 post-install patches to Big Sur BEFORE enabling AMFI/LV. That worked!
Lesson learned: If you have previously applied post-install patches with OCLP 0.6.6 or older to a volume with AMFI/LV disabled, install post-install patches with OCLP 0.6.7Beta2 (or newer) BEFORE enabling AMFI/LV.