How long do I need to have insurance before it can cover a surgery

Sorry if this is a dumb question (also didnt know what to flair this).

I currently dont have health insurance, never have (self employed too so dont get anything from work), but I plan to get a bisalp sometime within the next year. Wasn’t planning on doing it so soon but things changed and I’m going to need it done asap.

My research shows that a bisalp as a form of permanent birth control (which is the reason im doing it) is legally required to be covered 100% by insurance as long as the insurance I use follows ACA guidelines and its billed under the correct codes. So I am now looking around to get a suitable insurance, really for the sole purpose of covering the cost of this surgery.

My question is, do I have to wait a certain amount of time after getting insurance before it can cover my surgery? I am hearing things about how bisalps might not be covered by ACA compliant insurances anymore after the elections. So I am sort of desperate to get this done asap without waiting too long.