You might get in with VIP..

BUT you might have a note linked to your passport which might stop you entering. I would first speak to a visa agent who has good connections (or visit an embassy) and see if you have a note from border immigration in your passport. I once had a note in my passport stating I wasn’t allowed to apply for a tourist extension, the visa agent helped me

Maybe your DTV rejection is related to the denied entry. Border runs alone aren’t usually a problem if you don’t have a note in the passport, my partner and I did quite a few before our DTV was approved.

But maybe it’s not based on this at all and it’s something else. Are you sure you met all criteria for the application? The 500k for 3m, 6 month course, evidence you can support yourself, reputable gym/course with the certifications?

I don’t remember exactly, was there a question in the application about being denied entry or denied a visa? If applicable to you, were you honest in reply to that question?

Given you want to stay in Thailand longer term, I would speak to agent, ask if you have a note in your passport, get help from them and re-apply for DTV.

Why try another visa when DTV gives more time and is cheaper. Sort out the issue rather than try and throw it under the rug! Good luck