In Pattaya it is forbidden to rent Airbnb apartments shorter than 30 days.
Therefor you see mostly 1 month rentals on airbnb.
I wouldn't swim in the sea in Pattaya. Too dirty. Better use the hotel pool.
I would go 1 month Pattaya, go there directly with a taxi from the airport.
Or with the big bus (downstairs in the airport).
Never take a small mini bus if you want to live longer.
https://www.namstaxiladydrivers.com/
Than you want to travel more, so you need to go to Bangkok, stay there 1 or 2 weeks.