MB: ASUS_ProArt_x87E. There are two fan brackets on the north and south of the AMD chip. These were removed and the GA II standoff studs screwed in (partly). Screwing in the studs all the way would have punctured the MB and would have ruined the bracket screw holes.
Then, with studs inserted, the pump with the AM4/5 bracket was placed on top of the studs. It was not possible to screw the bracket into the studs and, if successful, the pump would not touch the chip.
I then removed a stud and inserted it into one of the bracket screws. No luck tightening the bracket screw.
Separate to this I looked at several youtube videos on installation. All of them used a different bracket and the online installation guide at
https://lian-li.com showed the same bracket (this one attaches to the fan brackets, unlike the one I have).
And so after several failures, I attempted to contact lian-li using their (
https://lian-li.com/contact-us) form. After 4 or 5 failures, I looked at the HTML for the "Submit" button on the form, and saw that it did nothing. I suspect it has been disabled.
I bought this thing from Amazon. My guess is that the vendor selling through Amazon is trying to dump all the old gear, which works for Intel chips but not for AMD chips. At this point I'm about ready to get either another GA II or another AIO setup from Microcenter.