There are three routes to apply: digital nomad, soft power, and dependent. For example, If one spouse is a digital nomad and the other isn’t, they can apply as a dependent of the spouse who is a digital nomad. That being said, they still have to fulfill the other requirements, such as 500k
First, it is a way to confirm you are in the Netherlands and second they want to understand why you need the DTV vs. 6 month tourist visa. They might want you to log into your account and show the money. No need to get stressed. Be honest and all will go well
The DTV is less than a year old and requires one to apply outside of the country. It is very different than the type of visas one can convert to within country. I am guessing that those agents with 1000* 5 star reviews received those reviews based on retirement and work-related visas. Furthermore, each embassy has unique processes. An agent isn’t going to know the process for each embassy. I would suggest the OP to join the DTV Facebook page and look at posts related to others who have succeeded and who have failed in using sponsorship. Figure out if certain embassies seem to accept more often and sponsored by who.