YES, it's posted at immigration. If TR visa NO, possibly visa exempt. There are two lines at immigration for foreigners. One for VOA and one for Foreign Passports. The line for foreign Passports only askes for Passport, eVisa and Boarding pass. It too is posted. I have NEVER been asked by an airline for my departure ticket. Other's say they have but it really isn't their responsibility. They are not immigration. I arrived on a TR visa with a one-way ticket. Had to get a round-trip ticket for the eVisa app but cancelled within 24 hrs and got my money back.
XE but you have to be in the US not Thailand. If you use a Thai IP address it won't work. If you have a VPN it might work in Thailand. Their net rate is better than Wise too.
The TR eVisa app will require you to have a DEPARTURE ticket. However, I got in with a one-way ticket. I just bought a round trip ticket to get the confirmation email for the app and then cancelled it within 24 hrs. I WAS NOT ASKED FOR MY DEPARTURE TICKET AT IMMIGRATION AND THE SIGN SAYS PRESENT PASSPORT, EVISA AND BOARDING PASS. NO DEPARTURE TICKET. You only need to present departure ticket if you arrive visa on arrival, possibly visa exempt. Some have said the airline asks for it but they should not care because they are not immigration. American Airlines / Cathay did not ask for it. Cathay did ask for my vaccination record but I think that requirement is going away.