FOUND THE PROBLEM. It was "(3) There's an undocumented 'special configuration' for Wii64 that needs to be applied."
I went through many more forum posts but ultimately found the answers in old github threads, right on the Wii64 github page. Smart place to look, right? There are a number of posts talking about
the clock divider and it needing to be set to 1 to take advantage of the overclock. Here are just a few examples:
https://github.com/emukidid/Wii64/issues/38#issuecomment-758165052
https://github.com/emukidid/Wii64/issues/28#issuecomment-699703561
https://github.com/emukidid/Wii64/issues/17#issue-312644268
CPU Divider Settings:
1 = Unlocked Wii64 (A.K.A. WiiVC)
2 = Wii CPU speeds (A.K.A vWii)
3 = GCN CPU speeds
Now, due to the following request, the CPU Clock Divider was defaulted to 2:
https://github.com/emukidid/Wii64/issues/39#issuecomment-900210179
It's not a bad idea since some games do run good enough or surprisingly are just more playable when using vWii CPU speed*. However, since there's no documentation stating CPU Clock Divider needs to be set to 1 for overclock speeds, most people will probably be playing with placebo (a la the many youtube videos I've seen). What really bugs me though is that I did change the clock divider setting, but I must have been doing it on vWii and my physical Wii, and not with the overclocked forwarder.
It also doesn't help that the documentation is inconsistent**.
Regarding the Wii64 forwarders on the main post of this thread, I can confirm they are NOT CPU UNLOCKED***.