Posting because this group has been very helpful.
DTV success in HCMC, Vietnam. Soft Power - Muay Thai.
Applied from Danang on Nov. 27 around 11am, received the visa today, Dec. 4 around 1pm. 5 business days as advertised. Provided 6 months of bank statements, including a recent screenshot of my balance because my most recent statement only covered until Oct. 30 (all over 500k THB), relevant paperwork from the gym, proof of presence in Vietnam (photo of VN visa stamp, VN evisa, hotel booking and receipt combined into a PDF). Did not receive any requests for additional documentation. Fairly painless process.
Thanks everyone, and good luck.