my two OW-boards are based on Mediatek SoC, designed in 2019, they are premium SBCs (150 euro each), they only have two miniPCIe slots, one is shared with the sATA lane, and it's mutually exclusive, either you use mini PCI, or you use sATA lane, you can't have both.
Another (cheaper, ~60 euro) example? the RBM33G, designed in December 2017, it has three miniPCIe lanes, two miniPCIe slots and M.2 slot, but that's because it's a router!
In my opinion it's already a good thing that the RPI-v5 has an exported PCIe lane, and it's a great thing, with which you can widely do great things.
(and by the way what do you have to do with much more bandwidth?)