Something like this. Since Logitech doesn't make type-C RF transceiver, this kind of adaptor is therefore the smallest solution to plug their type-A into your type-C ports on the Mac / dock / hub / Studio Display. RF transceivers themselves are fine but they are small and short, when buried in like a generic 10 port UAB type-A hub you can subject to that 3rd party's ability to properly shield, or the rest of the cables that you plug into that hub as well. Using the back ports of the Studio Display keeps the RF antenna higher up above desk level with only one bounce to the back wall needed. At least that's my experience with using them in a crowded desktop cabling setup. (And I didn't notice the G13 is a wired assistive input device, I thought it was one of the G lineup full KBs.)
Thanks, that is really helpful! I was now planning to just attach the mouse dongle to my old Cinema Display, which has 3 USB-A ports on the back. The Cinema Display itself would be attached to the USB-A hub. That should work as well, right? If not, I will go with your suggestion.
Well yes just get a multi-bay DAS enclosure if that's what you want. That said if I were you I would seriously looking thunderbolt enclosures for 4bay+, due to bandwidth and stability. Also such TB enclosures typically have a pass-through port so you don't lose that TB4 port entirely in this chain. But if it stays USB (type-C or not) there's nothing wrong with it.
My idea was that it would probably be best to get a cheaper enclosure (USB) for now and re-asses in something like 6 months, because I expect new products to come out, motivated by the release of the Mac Studio. Also I plan on getting a fast NVME SSD in its own TB4 enclosure for demanding work (also in the diagram).
For scratch disk it depends on how aggressive your workflow / app is. In the HDD days since disck are much more prone to wear and tear so a dedicated sacrificial scratch disk made a lot of sense. Nowadays the threshold of SSDs hold it much higher so it is hard to say if a normal user should need this. But since you already have the hardware, you can test how its reading and writing performs against your internal SDD to determine later.
I don't yet have the drive I would use for an external scratch disk, I'd have to buy that. Basically, I am also coming from the school of thought that you should always physically separate system, scratch and media drives. But it seems that belief might be outdated, especially with how fast these internal SSDs are. And it would really simplify things overall...