As other threads in this board attest, CX has shifted its schedules frequently during the pandemic while QR has had a pretty consistent record of flying its scheduled flights. For peace of mind, if I was in your position I'd be temped to buy a QR ticket (one way runs around 500 euros in economy in coming weeks). Relying on the prospect of CX sorting you out here will raise your stress levels. If they do, great, and maybe you can change the QR ticket, and if they don't, then you have more peace of mind. Good luck.