Hi there,
I'm sorry to hear about your journey so far mate but I'm glad you're keeping your head up. Let me start by saying a great profile is a great profile, regardless of round. That said, a lot of the seats on the bus for these programs have been filled up. Most programs are now in the position where they get to pick and choose the perfect final few candidates. You have interesting role (still in an IT-esque firm but more on corp strat), an amazing GMAT (congrats), and a pretty decent GPA from a great school. (You are a tad on the older side but that's not the end of the world as long as your story makes sense.) However, so did a lot of applicants in R1 and R2. So the seats that were set aside for folks of your background, while not absolute, are going to be mostly filled.
This doesn't mean a R3 application is a lost cause, but it merely stresses the absolute importance of your story. You can't leave a doubt in their mind as to why you want to attend. As gmatfighter pointed out, UNC is already in R4 and definitely seeing an uptick in applications. Tepper is fairly competitive as well.
The question to you is now that you were dinged from ISB and Oxford, do you want to throw in a couple of apps in R3/4, risk being dinged, and be a reapplicant next fall, or just wait and hit R1 hard next year. If you have the time now to put together a really great set of apps, go ahead and apply. You're not getting any younger and if you get dinged, that's ok, you're going to be banking on R1 next year anyway. If you don't have the time, then don't waste the application real estate. As a reapplicant, you usually get a streamlined app and they reuse materials from your last application. But if your last application wasn't all that great, then it won't help.
Another option is to put your application through a
Ding Review. We look through every part of your previous application and give you tactical advice on what could be improved.
Let me know if you have any questions - new or on what I wrote above. We're happy to help you figure this out.
Cheers!
Bhavik