A Thundebolt controller is a PCIe 3.0x4 device.
A 10 GbE NIC is a PCIe 3.0x4 (Aquantia) or x8 device (typical server NIC).
These need lanes anyway.
In all fairness, these are your own very specific requirements. Not everyone needs Thunderbolt. Not everyone needs 10 GbE. Not everyone needs WiFi/BT. Few need to plug an Apollo card.
You want them all, and that's more I/O than manufacturers care to provide—with the added complication that some of this I/O (namely Thunderbolt, or X710 NIC) may be
too new to be supported by macOS and useful to you if provided on-board.
Compared with the previous time we had this conversation you've raised the bar with 3*NVMe on top of the 5*PCIe slots.
X299/C422 and C621(A) boards have plenty of PCIe lanes (and memory channels), but I understand that you also seek maximal
single-threaded performance for audio rather than multi-threaded excellence. (Which raises the question whether the 13900K is really the best CPU for your use case…)
You can actually have that much I/O in a consumer platform for high-clock CPUs with older generations: AsRock W480 Creator and Z490 Aqua have all the slots you want (5*PCIe + 3*M.2)
with Thunderbolt 3 and 10GbE Aquantia already on-board! But maybe Comet Lake is not enough of an upgrade over your i9-9900K, or the extra bandwidth of DDR5 is part of the requirements.
Well, I've found a LGA1700 motherboard for you:
Asus Pro WS W680-ACE.
2x PCIe 5.0 x16 (1x x16, 1x x8) => GPU, 10 GbE NIC (and dual i225 on-board)
2x PCIe 3.0 x16 (x4) => Thunderbolt, UAD or WiFi/BT
1x PCIe 3.0 x1 => UAD or WiFi/BT… if the CNVi slot cannot take a suitable module
2x M.2/M-Key (PCIe 4.0 x4, 2280/2260/2242), 1x M.2/M-Key (PCIe 4.0 x4, 22110/2280/2260/2242)
It's not Z790 (there will be no W
780 anyway, and W7
90 is something completely different) but it will take a 13th generation Core and DDR5.