After some fucking around, I fixed a few things but not what I wanted. Indeed, the VAE was fucked and I had to click some buttons to make it load the file properly. I think it was trying to pull one baked into the model. Once that got working, the XL model started showing signs of life and after I gave it a 32 gig page file on my M2 drive, it started working.
The gen speed is fine, but it still sucks. The images coming out of it are still obviously unfinished and rudimentary. Here's a comparison. On the left is what I got from an anything 4.5 a few years ago on an online generator on the right is what I'm getting now from autismmixsdxl with the exact same tags. And in higher resolution.

>>2975031
I should really go to sleep soon, but I'll try and work through that tomorrow.