I do agree that big part of why they support Trump is for anti-regulation reasons. But, it is also a fact that Trump is one of them, a businessman, not a politician. With Trump they can now discuss more business and less policies. There is a certain dealing of business right now that seems not at all transparent. And in this, the amount of public simping is really weird to what usually happens, everybody praising Trump even before he was taking office, and even tiktok, "coming out" as whatever etc.
Oligarchs want less regulation, but they also want these beefy government contracts. They want weaker government to regulate them and stronger government to protect them and bully other countries. Way I see it, what they actually want is control of the government, and with Trump they have it (more than before).
That person is much more of a politician than a businessman.