Getting the visa is one thing, but getting through Thailand immigration should be a concern for you. Especially if after completing your ED visa you border bounced to get visa exempt entry and extension. “Immigrating without documentation.” Your US passport should get you back in on a border hop for 30 days plus 30 day extension. If I were you and it was me, I would then get back to the US. It seems that SETVs obtained in Southeast Asia are red flags to Thailand immigration.