There are some exceptions, but I haven't seen one with for example four x16 slots that support PCIe 5.0 x4 lanes with bifurcation.
E.g. https://www.ebay.co.uk/itm/126656188922
Most motherboards don’t go beyond 2x8 with 2x16 physical slots because there is little actual use for it and it costs quite a bit of money.
Asus 5.0 Hyper M.2 with yield 4x4x4x4 in a board that is setup for bifurcation of PCIE slot 1 like that.
I have run 4 GPUs this way and it works very well.
There are some exceptions, but I haven't seen one with for example four x16 slots that support PCIe 5.0 x4 lanes with bifurcation.