I am in a similar situation, travelling to SYD with previous +ve pcr despite being 4x vexed. Australia is very clear on requirements for the letter and I wrote Qatar on twitter and they made it clear that it is the requirement of the final destination that you must meet. I would guess this is coming up more and more and you must show a +ve pcr.

I would print out everything.

for data points. -ve pcr 28/12, -ve Rat 30/12, - ve RAT 3/1 , +ve pcr 4/1, and - RAT 5/1

genrally just felt like absolute .... for 2-3 days. Lethargy, cough, loss of taste. And not helped by +ve pcr coming in now that I am basically recovered and after - RATs.

KF