Can I board a flight to Thailand with a 60-day return ticket on a 30-day exempt visa?

Hello everyone, I do hope you are all well and having a good night. I like to ask something. I'm planning to visit Phuket on exempt visa with the 30 extension. They require a 30 days return ticket. Can I purchase a 60 days return ticket for that or there's a risk they will not let me board the plane or maybe I will also have problem with the immigration in Phuket? Is there another solution to this? Thank you very much in advance for your help. Have a peaceful night.