I am quite curious why there are only so many queer identities that can feature on hellaverse pride merch. If you aren't bi-, lesbian, asexual, pan-, transgender, hetero-, or a gay man, you get a generic rainbow flag to imply you're part of the queer community but not specify how. This isn't even due to A24 or Amazon, this pattern starts in Helluva Boss merch from before the... whatever led to it being partly funded by Amazon. This is to say, for a show that prides itself on its queerness, its queerness is limited.
You could argue that they're only using these identities because they are well known. While I would agree that these are some of the most widely known flags, I would also ask why should general knowledge matter? This could be a teaching moment, a community building moment. Using the unlabeled orientation or unlabeled gender flag, using an aromantic or aroace or agender flag, using an omnisexual flag, using different versions of the rainbow flag. People who don't know would ask what they mean, and they would learn. The shows could create a small legacy in broadening its audience's knowledge on queer identities & history, broadening mainstream knowledge on queer identities & history.
Going back to the "well known" argument, there is one flag that is grouped with these common ones that is yet to appear — non-binary. Arguably also intersex, and also transgender on a man character. If they're set on only using the "commonplace" identities, why aren't these present?