If you didn’t know, I’ve been calling Operation Hope “Ope Hope” because, while I am not midwestern, I am descended from them and married to one. So “ope” is a big part of my life.
Tonight, Stephen Colbert did a funny bit: https://youtu.be/gQ8MNuYdI-Q?si=nMWKfsUp5J7YW6yf&t=260. Made my evening. 
I am a midwesterner and I remember when I realized I unconciously say “ope” on a regular basis. Now my 1 year old also says it.
I’m originally from the Chicago area and grew up on the Northwest side and the NW suburbs.So I’m definitely a Midwesterner. But I never noticed “ope”!
My guess is it’s one of those little day to day things you don’t necessarily notice. Who knows, maybe I even used to say it. I’ve been in Tennessee for 16 years now and I don’t think I say it, but I’ll have to watch out for it from me and my wife (who also grew up in Illinois) and next time I see my family from Illinois.
But I definitely do the “yeah no” and “no yeah” thing, lol.
I thought “yeah no” and “no yeah” was Californian. Apparently not exclusively.
I am in Michigan, and i have never notice “ope” either. It has always just been ‘oops’, which has always been ‘normal’ to me. In fact, i have never even heard of ‘ope’ until about two years ago.