I am on 15.7.9 and I have had uptimes in the high 50s with weekly local model usage, I even tried GLM5.2 streaming from SSD and I have not noticed any slowdowns after at all. I guess you are right about 26 and 27. Dang, the more I hear about 26 I am just so glad that I did not update. What version of macOS are you on? 26 or 27? Have you considered doing a custom backup and restoring manually to 15.7?
I don't think I would downgrade though. I just hope this gets fixed someday... I can deal with the terrible memory bandwidth but I don't like to reboot.
(That said, macOS is so, so much better at reboots than Windows)
But my GLM5.2 is not 8TB, it is only around 200GB and works pretty well. (0.9tok/sec from a 40Gbps NVMe)
Also, it's very rare for people to have the 8TB option on Macs - it's got to be a $1600+ option, huh? So not very common, which is why I assumed it meant something else.