What should I know about switching from a Non-B visa to a DTV while applying from neighboring countries?

Good day all...looking for advice.

My situation:

* British citizen.

* Currently in Thailand on a Non-B visa with a 6-month work permit.

* I won't be renewing it when it expires.

* My plan is to leave Thailand and apply for the DTV from either Laos, Vietnam or Cambodia.

I'll be applying under the Workation category. I already have a legitimate remote job lined up, so I'll have a signed contract and the required proof of funds.

My questions are:

1. Has anyone switched directly from a Non-B visa to a DTV? Any issues?

2. As this will be a new remote job, I won't have any payment history from the company yet. Is a signed contract normally sufficient, or do i need to provide payslips or bank statements showing payments?

3. I could start the remote job, on the side, before my Non-B expires and begin receiving payments. However, I know this does not align with the purpose of my current Non B visa. If I did that, is there any chance the Thai embassy processing my DTV application would see that and lead to a rejection?

I'd really appreciate hearing from anyone who's been through a similar situation, especially if you applied recently from Laos, Vietnam or Cambodia. Thanks!