I am a Spanish citizen, living in Canada. I would like to fly back home (from CAN to ESP). Do I need a PCR test? I found conflicting information online, and also my own past experience. Here's some details:

• I am an adult.
• I am fully vaccinated (two shots), Pfizer, both done in Spain (so I have EU certificate).

My impression is that I do not need any negative tests (neither rapid antigen test nor PCR). But I've been flying back and forth in the past two years and frequently had issues (had to reschedule flights, redo tests, etc.). How can I maximize my chances of success? Is there for example an official document I could take to the airport in case they do not let me through? Or would this be useless?

(The obvious answer is to get a PCR test anyway, just in case, but it is not easy to get an appointment right now: there are no clinics nearby and they seem to be overbooked. Also, I strongly dislike the only clinic that is accessible via public transport because the last time I almost missed my flight as they would not give me my results in time, and asked for extra money to do it faster, which I could not refuse as I was already at the airport.)