I never thought I would do this, but ... (deep breath) ... I recommend Air France.
I think for this length of flight, with all the wheelchair hassles getting on and off the plane and in and out of airports, a stopover is really not worth it (unless there is somewhere you'd like to go on the way, for its own sake). So I'd recommend a direct flight, and the Air France premium economy is really very good, not like the "economy plus" jokes on some other carriers. Big wide seats, plenty of leg room. I was pleasantly surprised when, with some trepidation, I flew AF PE to Shanghai a couple of years ago. It was keenly priced then - less than economy on the competition - but that has likely changed.
Many Air France horror stories involve the transit in Paris - but since you're starting from there, that doesn't apply.
The Gulf carriers (Qatar, Emirates, etc) are all very good in my experience, and I'm sure will look after you, but I just think the stopover will add complications, hassle and opportunities for things to go wrong - so that you won't arrive in Bangkok any more rested than if you'd flown direct.