I will point out that if you use ZFS instead of btrfs, you can specify drives to be detected via their serial number names rather than their attachment points, so a reconnect will not require a reboot.
Still, don't depend on USB for anything meant to be permanently connected.
I've wondered if my experience is different because I'm using single disks (but still ZFS) instead of any RAID. There is rarely transfer happening across all of the disks.
Unfortunately, where I need it the most - the router which is also a NAS - can't use directly-powered USB HDDs. Not enough ports. I had to use a hub. I tried 4 models, two self-powered and two powered by router's USB, and none of them was stable. I also tried 3 models of USB-SATA adapters. Two self-powered, one powered by hub (connected to the hubs that had separate power - didn't work otherwise). None of them was stable. It was always the USB-SATA adapters/racks that disconnected, not the hubs.
Then I bought a mPCIe 4-port SATA controller, Marvell chip. Didn't work. It freeze randomly and woudn't even unfreeze with a router reboot. Possibly too much power draw. Then I put a 2-port SATA, ASM1062 and a port replicator. That one works. 2 years and not one disconnect. The cables are a complete mess.
The Terramaster one is pretty widely used in home setups and seems perfectly fine.