A 200mm hose adapter I made for my Vonroc SU501AC Portable Split Air Conditioner. It can fit a 200mm diameter air duct that is fixed using a cable tie. The adapter sits flush against the AC exhaust but is not fixed. I use some scotch tape and a chair as a guide to ensure it stays in place.

I printed it using PLA on a Bambu Lab P1S. Split in half vertically and then with the hose-side down. You might need supports in order to print the part that sits flush against the AC.