Yeah, not much at gen 2x2, particularly if you want hardware RAID. While I get hit for the Unitek Solidforce I’m not finding other JMS586A or JMS586U implementations. The lack of ASM2364 duals suggests it doesn’t support x2/x2 bifurcation.
Orico, Sabrent, StarTech, Yottamaster, a sanctions violating brand, and a bunch of Maiwo equivalents all offer dual USB 10 Gb.
FWIW, the solution I’ve used for the past decade and some is just to have two USB storage devices, backing one up to the other. Not as elegant but it works fine.