Really disappointing to hear about the single v1 batch after having waited for so long. Obviously I'm going to get over this (and I'm not that upset), but allow me a post to vent my frustration and provide some constructive feedback based on what little I know of your situation/the facts. I have worked in mechanical engineering design for production for well over a decade, in multiple industries (defense, consumer electronics, automotive), and I can say this situation sounds like a failure in either sales forecasting or production management. What I can say for sure that this has been a failure of communication.
Clearer and proactive communication may have avoided a lot of the disappointment: how many units were planned in the batch, what the predicted sales rate was before production, what the actual sales rate was (and based on this, the estimated sell-out date). Obviously you're not obligated to share any of these details, but I don't see how it would hurt you to do so. Most importantly, it would have been nice to communicate the potential for only a single batch of v1 cases. At some point, you considered/decided to not produce any more batches but waited to tell customers/forum that if they had not purchased a case in the first 4 weeks of availability, that they are now no longer able to get one (at least outside of a 2nd-hand market). On top of this, you canceled your plan for a Q4 Newegg release after advertising it to your would-be US customers, who now have to purchase another case/brand if they want to build in 2023 and likely in 2024. All of this, for a v2 which you say isn't better than v1, just different?
From a business standpoint, this does not make a lot of sense. You are forgoing profit from additional batches on a completed v1 design, a design that is very popular (your biggest batch of cases ever, sold out in 4 weeks), and a design for which Lian Li already knows how to manufacture and assemble. Your comparison to Nvidia is not fitting, because sold out Nvidia GPUs is temporary and goes away once demand reaches equilibrium with supply (assuming Nvidia is not creating artificial scarcity). With the C4-SFX v1, there is no equilibrium because now your supply is zero and there is no additional batches. Instead of the v1 profits you could be making with additional batches, you are shifting focus to develop a v2 case that "does nothing better than the v1". There must be something that convinced you to immediately drop v1 and start v2. I suspect you are considering the greater sales/profit resulting from more color options, mATX support, and flat packing which will decrease distribution/shipping/cargo costs.
As a designer, you must know that a v2 is not without its own risks. You said the interior will be similar to v1, but designing for flat packing can quickly and significantly change that. The exterior design is quite different, different enough that its design comes with potentially large development risks, like unknown unknowns that will lead to delays. You have already experienced first-hand the difficulty and delays of v1, but now you believe a potentially very different v2 will release in 9 months? This is wishful thinking. In those same 9 months, competitors can release directly competing SFF cases.
What I don't understand is: why not partner with Lian Li to continue building the v1? Even if they take a portion of the profits, you would still profit from sales, and I bet there will probably be a lot of sales. They're aren't a lot of cases like the v1 currently, so until competing companies release competing cases, the C4-SFX has a large advantage. You could hand off all v1 effort to Lian Li so that you are free to develop v2 in parallel. Focus on design (your personal core strength and differentiator, and probably your passion) and outsource the planning, manufacturing, production, logistics, marketing, etc to someone else. In fact, and this is more of a personal option, it may be worth it to work for Lian Li as a design lead. Maybe they would hire you to be the head of their "Dan" line of cases. While working for them, you can observe how their other departments operate and use those learnings to one day build up your own production company with mass produced, wildly successful cases. Just a thought, and again, may make no sense because I have no idea about your situation.
Anyway, rant over. Good luck with the v2 development. I'll probably get a Q58 or SSUPD case in the meantime. Cheers.