Employment certificate is different than contract, they want it to state that you're still employed and remote work is authorized including in Thailand.
Please get creative, submit the most recent statement and a screenshot of the transactions since. Include a brief note stating your statement is month end and the screenshot is to account for the time since.
They discontinue visas for being unpopular. Thailand is doing everything it can to encourage visitors, there must have been a half dozen policy changes in the last year or two towards that goal. Expanding visa exempt country list, lengthening of visa exempt stay duration, remove limitations on visa exempt entries by land, increase VOA stay limits, add countries to VOA list, introduce a dirt cheap no brainer 5 year DTV, that almost anyone and his dog can qualify for, and if you can't qualify for it financially mommy can sponsor you. It's manna from heaven to one of the world's top destinations. They didn't require background checks, health insurance, medical fitness, the MFA has literally flung the doors open.
in truth nobody knows, but better than highly likely it's 1900 baht, but the big unknown is what will immigration request to do an extension, such as banked 500K, updated documents etc.