"Maybe you can stop with the disingenuous "evolutionists" and just call these people by their professions: biologists and geneticists."
There are many biologists and geneticists that don't believe in unguided, large-scale adaptation (evolution) as origin of all life. Many are in the intelligent design camp. So, you can't speak for all biologists and geneticists. Instead, I'm countering evolutionists since it's them biologists, geneticists, complexity theorists, and systems people (me) disagree with.
"If it was really such an easy ability to acquire you'd think that more than 1 of the 12 lines would have achieved it after 75k+ generations."
We believe in small-scale adaptations ("micro-evolution"). Things that turn something on or off in existing genetic code, like this example per my link, would fit in there. So would antibiotic resistance in bacteria. We still don't see them forming new organs or anything substantial like evolutionists say happened for most (all?) species on Earth.
Far as difficulty, we believe it's difficult. Actually, those of us opposing macro-evolution say that micro-evolution can be so hard for things like citrate that it furthers our doubt in their larger claims. Especially when the features have irreducible complexity at mind-boggling levels.
" the development of species over time with a fossil record and existing species that looks exactly like an evolutionary tree, including physical traits, similarity in genetics"
You all just describe it that way, like marketing. I've already noted that evolutionists usually believe in evolution a priori, come up with evolutionary explanations for anything they observe, ignore what is contrary to the theory, and publish what supports the general theory. They certainly present things in a way that looks like they evolved. Many specific examples they put forth in the past turned out to not be what they said, too.
Until the systemic bias is eliminated, I don't trust such presentations of cherry-picked data over observations of actual evolution. Further, the prior predictions of evolution didn't match the observations. They promoted it harder and made excuses instead of dropping it. Since then, we've learned the universe and body are even more complex than originally anticipated. Macro-evolution is provably harder than believed when evolution was failing its predictions.
Even as macro-evolution became harder, we saw people posit evolutionary algorithms with the Humies Awards as proof of its design. I was one of those people before becoming Christian because pro-evolution statements with those cherry-picked presentations were all I was ever exposed to. Now, I get to see several sides. In any case, re-reviewing the work on evolutionary algorithms and large, language models (eg GPT) show they take an enormous amount of intelligent design to accomplish anything useful. Everything from the substrate to the math to the implementation to the environmental interface.
" suggest that their ancestors may have had legs"
"since apparently some muscles are still connected to them. But regardless of vestigiality, they're clearly remains of legs."
This is an example of what I'm talking about. They're actually just bones that look kind of like leg bones. So, that means they're either leg bones or that legs and those use a similar structure for a purpose. Instead of proof of structural similarity, you say it's proof of evolution because your worldview (evolution) dictates starting everything with its conclusions as premises. Even with muscle tissue, you have to think it's vestigial or a leg because evolution makes you want to.
Note: Interestingly, the Bible does have a serpent with legs that becomes a snake. That's presented as a supernatural event, though, so I can't use it here. Plus, it's testimony, not science.
"Does it sound like a grand conspiracy to you?"
It is if you call organizational bias a conspiracy. It's a fact that they wouldn't allow competing theories in most places. The person would be mocked, rejected by the journal, or not even get funded. With that happening, all research output is pro-evolution because those controlling the human processes are pro-evolution. Any science that becomes dogma with strong, political motivation is self-reinforcing.
"so IF you have the option of taking the role of an intelligent designer, that is often the quickest way to get stuff done."
Straight-forward creation is the fastest route for an intelligent designer capable of sustaining the whole universe. Ours can and did. Whether or not God worked through evolution from there is an open question.
Empirical observations of the only intelligent designers we know, humans, show they create their fictional universes rapidly before forcing things to happen with in-universe laws. Think filming a movie vs what happens in the movie's universe. Even in the fictional universes, they often say they were evolved because things look that way. They weren't. The whole thing was shot in months to a year. Truth is we can't know by internal observation.