Is there a risk that my third Thailand Visa Exemption entry will not be granted after multiple entries this year?

You're asking a question that no one on this group can answer.. still, I'll give it a shot..

What you have in your favor is,

Even though you've gotten 60 visa exempt entry you haven't stayed the full length of the entry stamp, nor have you extended that at the immigration office for 30 more days (like people who live here on free entry stamps do).

Your stays have been short, and time out of country has been significant, as in your not just bouncing out/back to get a new 60 day free entry stamp (like people who live here on free entry stamps do).

And for this upcoming trip you're only here for 2 weeks you would have proof you're leaving the country in case you were questioned when you stamp in.

I would say you're a pretty safe bet to get right in without much problem when you come back in Nov.

Only you can decide whether to get the new Non-OA visa before you come here or just come back this time free stamp.

In my estimation you are doing exactly what tourists do, come here, tour and go back to your country. I don't see any abusive free stamp entry/stay history in what you're doing

But

I'm not the officer at passport control either.

Best of luck with it, safe travels