You can just use your old dual 512GB M3 Ultras until you get the M5s. Man, people always whine about something...
O shit, I didn't even think of that. I've got a few of those kicking around, honestly I was just using them as doorstops at this point.
They suggest a pair of Mac Studios w/ M5 Ultra chips and 512 GB of RAM. A single Mac Studio w/ M5 Ultra and half that RAM (256 GB) is around $11k, and the 512 GB option isn't even available yet. So.... yeah.