You might have more luck with Guard/Reserves and then just getting on AD orders for the waiver. And, as Rick said, I really wanna say I knew a couple folks in my OTS class that were Active Duty and close to or above 40 that were prior-enlisted.

As he also said, ANYTHING is waiverable if you find the right folks and put the legwork in yourself. But, those are two big keys. If you go to recruiters/Reserves/ANG and just say, "Hey, I wanna go to OTS but I'll need a waiver," they're going to likely just view it as too much work and tell you, "No." Especially in this cratering economy where they probably have/are expecting a glut of new applicants looking for the job security of Uncle Sam.

However, if you go to them with the paperwork filled out, a clear idea of what you need for a path forward, and maybe make a contact that can make a phone call or two for you and they just need to push the paperwork, you stand a fighting chance. Most people don't want you to give them a problem and they have to find your solution. But, if you make it as easy as possible for them to do their part to get you from A to B, they'll be much more willing to make it happen.

Source: a non-prior service dude that got a (Reserves) UPT slot at 36 (when the cutoff was still 30), commissioned through OTS at 37, and should have a set of wings (depending on Coronas and lockdowns) in less than 2 months at 38 years old. There's almost always a way to "Yes," it will just require a lot of extra hustle on your part. And luck, too, but you can make a lot of that with your own legwork.