What, specifically, are your needs that you are referring to?
If you know your only "high end" need is a ton of M.2 slots, you don't specifically have to limit yourself to just high end boards. You can always get a PCIe to M.2 expansion card: https://www.amazon.com/ASUS-M-2-X16-V2-Threadripper/dp/B07NQBQB6Z
With those, any LGA1700 board with at least 2 full x16 slots is viable.
Also I'm not too concerned with it as ultimately I will be using this, I was just hoping I could put off buying it a bit.
yes. You have to find one that's explicitly compatible. I couldn't tell you the technical details of how it's differentiated, only that both users and sellers have related that Gen4 must be specified on the card. (e.g. Asus sells a Hyper x16 that's Gen3 that's a separate listing from the Gen 4; it's similar to how riser cables must be listed Gen4 to support Gen4 speeds)
why $100 for 2, when you can spend $55 for 4?
https://www.amazon.com/ASUS-M-2-X16-V2-Threadripper/dp/B07NQBQB6Z