You’re supposed to apply from outside of Thailand. So don’t apply yet, you’ll have risk of losing application fee. Go to Vietnam or nearest country to apply, and stay there until you got approved.
You have to apply online through their portal. It’s same requirements, you need to provide address in Netherlands to be eligible to apply from that embassy. For flight ticket reservation is fine, you don’t need to purchase.
There were many posts about Rental or address in Thailand. Try this keyword in search box ‘rent’ or ‘rental’. Make sure to know why you were denied for entry on tourist visa, that might be an issue to get rejected even with DTV.
You can apply for you and dependents at the same time. For dependent, you just upload your portfolio and work related doc where the form asks to upload your main DTV holder’s stamp. I got mine and my wife’s dependent visa at the same time in Hanoi, took five working days.
You don’t have to wait for main applicant’s approval. I did mine with dependent wife’s application. Just re-upload main applicant’s portfolio pdf where they ask stamp of main DTV holder. But you still need 500K proof in your wife account or combined amount in main applicant’s account.
Guys, actually you can apply dependent, along with main DTV holder’s application. I did it in Hanoi, got mine and dependent for my wife on the same day.
I guess not eligible as staying in Thailand more than three months won’t consider tourist anymore. And you can only get refunds for purchases within three months.