Can a European citizen with an exemption visa on arrival extend their stay in Thailand for 30 days?

Hello everyone 😁 I was wondering if it's still possible for an European citizen with an exemption visa on arrival to extend it for 30 days once there? We plan on staying two month and hoping to do that instead of getting a flight outside the country and back. Also would it be a problem if the only return ticket we have is within 60 days and not 30? Are they really asking for a flight ticket to let you in the country? Thanks a lot