Can I book a flight out of Thailand to a different country than my country of origin on a TR visa with a COE?

I’m in the process of applying for a 60 day visa. I’m told though I may have started the process a little late for my 4 November departure date. My question is, if I change my plans and opt for the 30 day visa exemption and get an extension for 30 days once in thailand. My return flight is 6 weeks after my arrival in thailand so I understand I need to book a outward flight within those 30 days. Will they except a onward flight ticket to another Asian country ? Some of the Asian countries aren’t excepting non jabbed, or wanting a visa prior to flying. Will I get pulled up due the fact I won’t have a visa going to these countries ?? I don’t plan to fly out, just need to show this for a onward journey out of thailand. Tia.

@Michael *******

as Michael stated.