Make sure if you buy a Chinese brand that you buy the "international" version. Sometimes they will sell you the "China" version for cheaper, but it'll be missing a bunch of apps and basically useless outside of China!
That's good. I've always appreciated how Singapore doesn't do passport stamps, it's all electronic. Let's hope other countries like Thailand follow suit.
And what are you here for? Not to ask any questions related to Thailand or visas, but just to complain about other people's conduct and tell them to shut up.
Please consider that maybe you're part of the problem here!
Turkey is visa-free for Thai citizens. Make sure she has a return ticket within 30 days and proof of funds, and she should be fine. Also returning to the UK afterwards should be fine, as IIRC the UK visas are always multiple-entry.
UK visa is valid for visa-free entry in only a very few countries. Albania, North Macedonia and Morocco are examples I can think of off the top of my head. For Schengen area you will need an entirely separate visa. Turkey and Georgia are always visa-free for Thai citizens, as is the (internationally unrecognised) northern part of Cyprus.
From my experience of applying for the tourist e-Visa, you need at least convincing evidence that you are in the UK from when you apply until when you plan to leave. This means, if you are travelling from the UAE to Thailand, it's ok but you must show a flight ticket from the UK to the UAE before the flight to Thailand. IIRC the website won't restrict you from applying based on geolocation but in case it does, consider using a VPN and setting it to UK.