I'm not trying to be a dick, but it seems like you need to adjust your expectations a bit. From what I'm gathering here, your heart is set on XMod, the wait is either until July (or later now that you got out of line) and you figure out how to ship one to wherever you are, find one used, or go...
Pulled the trigger. These bad boys are in stock. I just got the email yesterday. https://www.maperformance.com/products/maperformance-catted-downpipe-2020-toyota-supra-a90-sup-mk5-dpc-gesi
Sooo close. I know piggybacks aren't fashionable anymore, but I'm pretty bullish (not using one myself quite yet) on JB4. For a long time, piggybacks were all we had. Might not get you all the bells and whistles, but it'll get us somewhere.
I doubt anyone has any in stock, because of the reason that you mentioned. Demand is high, and these are basically handmade. Your best/fastest bet would be to stay in the line you're in, rather than get in a different line at the end.
I have the Swift lowering springs, and they are -great-, they sit fine on the 2021.
I got them through @Meraki Autoworks, and they were delivered in a couple of days.