We had a similar delay recently (on UK passports), and had 12hrs until our next flight. instead of ~3 originally booked. We were travelling in J/Business class.

There were greeters on the jetbridge for seemingly every connecting location in Europe. When we presented, we were asked if we were fully vaccinated (we were), then we were given a hotel voucher, taken through the arrivals process (sent through the GCC passport queue), then bussed to a hotel in Doha for our layover before being picked up and returned to the airport later. We were also given a 100QAR meal voucher to use at the hotel.

I'm not sure what the experience would have been in Y, but once we got past all the J/F class greeter people on the jetbridge, there was a wall of people with signs up for economy class passengers. I'm afraid I don't know if they got similar treatment, but would guess they at least got something.

As above a lounge may be the best option if a hotel isn't arranged? You could message QR on WhatsApp to see if they tell you what's possible also?