I arrived last Friday with a one way ticket with my partner, we both have individual DTVs and we were not asked for an onward ticket, just to prove we have a DTV, which is the email and PDF download once approved. Easy peasy.
if you have anything else like a bank statement showing your address, merge it into 1 PDF with your licence. For example Wise allows your to print a proof of account letter.
I used my Airbnb to prove my address and added a note saying I am digital nomad so don't have a set address always
becuase it would be helpful to advise those who are applying, Visa's are linked to immigration no? Some of us have never been to Thailand and may not be fully aware of the requirements.
If you haven't watched this about the DTV, I watched this and immediately applied afterwards. Give it a watch, it's an exclusive interview with the man in the Thai Government who oversees the entire Visa program.
You can do it online too, but I think the only thing is you may need to show proof of where you are living... I did mine from Madrid, and just provided my Airbnb (the have travel option to prove you are staying there). I know some friends did it from their home country (applied with VPN set to home country).