The Thailand Pass system is used for Sandbox and AQ also (not just Test and Go). It has not allowed you to start new Test and Go apps since Dec 22, as you mentioned. Just wanted to clarify in case someone else reads this thread trying to make sense of everything!
If you have any issues, definitely reach out to the consulate and leave a message if they don’t answer. But also know that you can message me directly. I have been helping a lot of people get to Thailand throughout the last year and stay up to date on all the new processes and systems. Just shoot me a DM when you need anything!
You can choose any of the four consulates/embassy that are issuing visas (DC, LA, Chicago, and NYC). You used to be assigned based on a geographical map, but when they switched to a new online system it now allows you to choose. We have had a good experience with Chicago and D.C. you apply online first and then mail your passport and supporting documents. I would recommend USPS and send them priority with tracking.
I know someone who was just approved through the consulate in Chicago and a couple of others who have been approved in the last few months. I don’t think you need to worry about it. Thailand has eased up on approving O visas. As long as your paperwork is in order, you should be fine.