I ordered the Triguard car cover a couple weeks ago. I checked in with the parts department since it's been a while without a shipping update (I knew in advance it was going to take a while like many other accessories). They told me that mine was being "custom" made by CoverKing. I don't know if they are made on demand or by batch and orders for the ID.4 just haven't hit critical mass to stock yet.
Through VW Parts, there's actually some pretty significant savings compared to the direct custom options (though there may be some color choices that are unique).
Tip: check several dealers in your area. Some have default discounts on accessories. I have one nearby that discounts a flat 16% while the others are at MSRP.