I was living in Jomtien for a year until April this year... and went back to Chiang Mai.
I lived in Chiang Mai 2015 to 2017. Now Chiang Mai is a shadow of it's former "glory". I agree with the OP... Thai in Pattaya are not much friendlier than the very worst Thai found in Phuket.
Sadly Chiang Mai locals are better.. But not like 10 years
Thai people have had to put up with a lot since 2014. A lot! I think it's reflected in thier attitudes... humility was never a Thai characteristic and now I think they are just downright angry about it all.
I back in Jomtien as of Saturday... the air is fresher... it's MUCH more convenient for all sorts of things and it's EASY to find a really nice condo for 12k.