Hello mate. For questionable ED visas, they pull people aside, go into a separate area and asked them questions like “can you speak Thai”? “What is the name of your teacher?” etc. Failing this, they would not grant permission. This was very common and I know few people who got rejected this way.
imo, this visa is cooked. No chance it will continue on in current form with all the unintended applications. Thailand will kill it or they’ll make you resubmit all documents upon re-entry/extension.
Just write a letter of certification from your company on a company letterhead stating you are employed and can work remotely. Doesn’t have the be complicated wording, mine was literally just bullet points.