I’d start looking at upgrading the enclosures for your two external drives. The Mac Studio has four Thunderbolt-4 ports that can also handle USC-C. Apple traditionally configures two ports per BUS. If Apple has configured the Mac Studio the way they have other Macs, the two ports to the left run on the first BUS, and the two ports to the right run on the second BUS. The BUSes work independently and theoretically can reach their full in/out speed of 40Gb/s as long as the devices connected to them match that speed.
I’m not sure which Mac Studio you’ve ordered. The M1 Max should have two TB-4 BUSes on the back with a theoretical in/out speed of 40Gb/s and one USB-C BUS on the front with a theoretical in/out speed of 10Gb/s. The M1 Ultra should have three TB-4 BUSes, two on the back and one on the front, all theoretically running at 40Gb/s.
If you daisy-chain a TB-1 and TB-2 drives together and connect them to one of the TB-4 ports, you’ll only achieve the theoretical in/out speed of the slowest device, your TB-1 drive (10Gb/s) on that particular BUS. If you connect the TB-1 drive to one port on one TB-4 BUS and the TB-2 drive to a port on the other TB-4 BUS, you’ll at least be able to theoretically achieve the speeds of the two drives independently. TB-2’s in/out speed is 20Gb/s.
You’ll probably have a monitor that will need to be connected to one of the ports. It will run at its own in/out speed and will be a factor on the in/out rate of the BUS it’s connected to.