Looking to charter a yatch

We are a group of eight people planning a trip to Phuket in the last week of July.

We’re interested in booking a private yacht for a full day of island hopping, including Phi Phi and Maya Bay.

I was surprised by the number of charter companies available (although most of them look shady).

However, when I reached out to them, I haven’t received a response. I’m curious to know if it’s common to book private charters for smaller groups for island hopping and how I can proceed with the booking.

My budget for this trip is around $2000 to $3500 USD.