The SSD is only just Replaceable
Although you'll want to keep your expectations in check, the Mac Studio's storage isn't quite as fixed in stone as you may believe. According to an iFixit teardown of Apple's pro desktop, the SSD module can be replaced in certain conditions. Using Apple's Configurator program to execute a DFU restoration, the company was able to replace the drive with one of the same capacity (from another Mac Studio).
In the base model, you can't install a second module, and it's uncertain whether larger capacity will work. However, if Apple ever makes spare modules available through its self-repair program, you might be able to resuscitate the Mac Studio with one.
It's no surprise that the RAM incorporated into the M1 Max or Ultra chip can't be replaced.
With Torx screws (albeit a large number of them) and removable ports, the Mac Studio is easier to access than you may imagine. And, yes, the Mac Studio's cooling system is as enormous as you'd heard. The fans are larger than on other Macs, according to iFixit, and the base model's aluminum heatsink is six times heavier than the Mac mini's.
iFixit gave the Mac Studio a 6/10 for repairability after the breakdown. The repair business was most concerned about non-upgradable components, but it was also concerned about buried fans and the possibility of dust build-up. Although you're unlikely to use this system like a Mac Pro or a slew of PC towers, those limits are worth noting if you want to operate the Studio yourself.