A new team that would like to have a custom kit can request one from Zwift but my understanding is that process takes… some time. Until that custom kit is available the current selection of kits available at a low level, that are not tied to a particular team, is rather more limited. There are lots of kits in Zwift but the majority were unlocked via an event held long ago, and therefore now unavailable.
So this request is for a selection of generic “temporary” team kits to be made available thru openly published unlock codes. I do not know Zwift’s process for creating kits - but if it makes any difference these would not need to be complex, just distinguishable from one to another.
Every single kit available with an unlock code is associated to a team, organization, or product. The above request is for some kits that are independent of all of that.
The kits with unlock codes are available to anyone but if there are none you want to use then contact the events team as I mentioned. I don’t think you’ll get a quicker solution that will help you in the short term.
Your club has to have minimum number of members, minimum number of events run and minimum number of people doing those events.
So it’s a difficult process. I tried to do it for the IRL club which primarily rides big IRL events and is quite well known world wide. I gave up then the rest of the folks fairly well moved away from Zwift and focused only on IRL riding.