So, the plot in season five of Disco is hunting down clues left behind by scientists who uncovered the technology left behind by a precursor race of alien beings who panspermiad their genetics all over the galaxy, resulting in all your favourite humanoids, like humans, Klingons, Romulans, and Cardassians, as seen in the TNG episode, "The Chase".
And the antagonists of the season are not actually the tragically dumb young lovers, Moll and L'ak, but instead appear to be the Breen. We've learned Breen are, as Captain William Shaw might say, goo people. Or at least they're semi-transparent so long as they're within the confines of their refrigeration suit. If L'ak is any indication they can take a more solid, humanoid form, but the Breen appear to prefer to be Sour Patch Kids.
I'm going to speculate that we will learn that the Breen are not actually one of the species who resulted from the Progenitors seeding the galaxy, and as such the Progenitor technology is of limited use for them.
Writer Carlos Cisco has indicated that they conceptualized the Breen's solid form as an adaptation that they developed over time, which would track with your idea.
And "The Chase" certainly left some wiggle room for there to be species that were untouched by the Progenitors:
Our scientists seeded the primordial oceans of many worlds, where life was in its infancy. The seed codes directed your evolution toward a physical form resembling ours. This body you see before you, which is, of course, shaped as yours is shaped, for you are the end result.
Writer Carlos Cisco has indicated that they conceptualized the Breen’s solid form as an adaptation that they developed over time
Interesting.
It's completely unrelated to the current Disco story arc, but that does make me wonder if the Vorta and other Dominion species would have been aware of the Breen's goo form. The Changelings evolved the ability to shapeshift over time, but were originally solids. having the Breen start out as the soundtrack producers for the "Spider-Man & Venom: Maximum Carnage" video game, and later develop a solid form might seem anathema to the Founders and their worshipers.
I had a similar thought. So far Disco (unlike in "The Chase") has implied that the progenitors seeded all life. I have a feeling it's meant to throw us off the trail a bit.