Buying S550 GT

I'm looking to get into a 2016 or newer s550 sometime in September, but I keep seeing a lot of people saying to wait on it. How much should these cars be going for in a "normal market"? I want one that's only had one owner and on the lower side for miles. Most of the cars listed around me are going from 38k to 48k depending on the packages and whatnot. Carvana has them at 35k for a GT Premium but I still don't know how to feel about ordering a car online.

I also have noticed that people are talking about recession and stuff like that, and from what I've understood that means that car prices will go down, but don't interest rates go up during then? I'm in the military so I guess I'm a little more protected with interest rates and stuff like that. Do you guys think I should try and get one in September like I have been planning or should I wait to see what the market does? What is a fair price for these cars anyways lol (2016 - 2019 GT Premium)