Is a 15-day hotel reservation sufficient for applying for a DTV from Japan?

Hello, everyone. I am planning to apply for a DTV (Destination Thailand Visa) from Japan. I have one question. When applying for the visa, there is a field to enter the place of stay. For how long did you all book a hotel before applying? Is a hotel reservation for about 15 days acceptable? (The embassy information stated that proof of a stay of 15 days or more in Thailand is required, but I was concerned whether applying with the minimum number of days might lead to a rejection.) I've also heard that once rejected, it can be difficult to get approval later, which is why I'm asking."