I can't reproduce you drives exactly, but I have just connected two external drives to give me the following:
3x NVME connected to motherboard
2x SATA mechanical HDs via motherboard
2x SATA SSDs via motherboard
1x NVME (external via USB)
1x mSATA (external via USB)
1x DVD RW Drive (external via USB)
That makes 10 right now, including the DVD drive and all seem to be working fine. So I don't think your issue is related to W11 Pro, I have the same OS. I don't know what your issue is I'm afraid. Any limitation mentioned on your motherboard manual? I have the 690 Hero, that's the only difference I think. Are you using a USB hub for your external drives? That might have a limitation, but seems unlikely unless it's faulty.
Z690 Hero, BIOS 2305, ME Firmware 220.127.116.116, 7000X Case, RM1000x PSU, i9 12900K, ASUS TUF OC 3090TI, 2 x 16GB Corsair RAM @ 5200MHz, Windows 11 Pro 22H2, Corsair H150i Elite AIO, 4x Corsair RGB fans, 3x M.2 NVME drives, 2x SATA SSDs, 2x SATA HDs.