"Passengers from all destinations served by Qatar Airways can continue to travel with the airline and transit through Hamad International Airport, the Best Airport in the Middle East and Third Best Airport in the World according to Skytrax,
subject to entry restrictions at their final destination. You will need to hold immigration approval to land at the final city in your itinerary that is operated by Qatar Airways, even if you are taking a connecting flight afterwards."
Per:
https://www.qatarairways.com/en/trav...19-update.html
Nor is there any indication on
https://www.qatarairways.com/en/trav...uirements.html that you need a PCR to transit DOH. There are a very few exceptions detailed here:
https://www.qatarairways.com/en/trav...19-update.html
"Effective 25 April 2021, all passengers travelling to Qatar
as their final destination need to present a negative COVID-19 PCR taken within 72 hours prior to their scheduled arrival time in Doha.
Effective 29 April 2021, passengers arriving or transiting in Qatar who have been
in or transited through India, Nepal, Bangladesh, Pakistan, Sri Lanka, and the Philippines need to present a negative COVID-19 PCR test taken within
48 hours prior to their scheduled departure time from these countries. "
Details are important.