Hi, literally all of them. I've had BKK, HKT, KUL and SIN flights cancelled, and have been toggling my final destination between them. It's typically multiple flights a day being consolidated into one flight, which triggers a 8+ hour schedule change. It also means that you can maximise your chances of schedule change flexibility by choosing your flights carefully - each time only one of my sectors was cancelled allowing me to change the whole itinerary

Tbh, can't complain - after an initial "computer says no", I've always had destination changes processed quickly and politely after checking with a supervisor. I've been calling the Qatar reservations number FWIW

Edited to add: I would normally get a refund, but I booked various tickets on a credit card that no longer exists, and it is *really complicated* to get your refund in a different form. I've already lost one Discover Qatar booking that was auto refunded and I've not been able to trace - but, in the scheme of things, $30 I can take or leave