Unless forced too, with visa requirements, or requests from your Thai bank to show proof of a tax return, and or residence, the truth is, most retirees in Thailand won't do anything, and just draw their pension and live their lives, if you don't register with the tax office, they don't even know you exist, I think most of the fuss is scare mongering, but what I said is just my opinion, time will tell.
I used the photo editor on my phone, and selected "collage" you can put two or more photos of your documents into one photo, and upload that, it was accepted for me on the Thai e-visa website.
some immigration offices send people away and tell them to return when they have 7 days or less remaining, I've witnessed them in the Pattaya jomtien office, sending people away with five days remaining, because it was so busy! and telling them to return when they have one or two remaining.
of course onward tickets are "fake" you can't use it to fly anywhere, like I said it doesn't appear like any other booking on the airlines website, because I've checked it, it only had my name and no other personal details, the point is if someone at some point decided to check it, it obviously isn't a genuine booking, it could cause you problems with airline staff, embassy staff, immigration staff, the price difference between an onward ticket and a genuine ticket is nothing, just buy a genuine ticket, the onward ticket I had I would have been embarrassed to show it anyone, and insult there intelligence into thinking it's real.
I bought an onward ticket once before, it just looked like something someone had made on a word document, sure enough it had a booking reference, which I entered into the airlines website, and only information it had on the booking was my name nothing else, It obviously wasn't a genuine booking, my point is if someone decided at some point to check it out, it was obviously "fake" and it would get rejected, I personally don't see the point when you can buy a genuine ticket to a neighbouring country, for near enough the same price 🤷
I was told my METV would be rejected with a bus or train ticket, needs to be a flight, they also said I need a ticket for returning to Thailand, to show the need for an METV, maybe some embassies are more flexible, I think the airlines issue is, if you get denied entry into Thailand, it's their responsibility to return you to where you came from, the Thais like you to have a ticket for leaving Thailand within the number of days your stamped in for, due to overstay worries.