The flying skills are not the problem when it comes to post covid safety. As has been mentioned the sim training and line sectors take care of brushing away the cobwebs. The bigger issue is the mental health of the returning pilots. Most are going to be under some financial or personal stress. For the Virgin pilots its the stress of the VA and their on-going future. For QF and JQ its still an uncertain future as even amongst the NB pilots there will be the uncertainty of fleet numbers as JQ has already stated that 20% of the NB roster is international flying. QF has stated that Christmas will only see a return to 50% of their pre-covid schedule.
Look at the PIA crash, they were pre=occupied with issues outside of the cockpit. A few years back there was the crew of an American (not the airline) domestic crew who overflew their destination by 150 miles because they were discussing post-merger seniority lists. The airlines and CASA are not capable of dealing with this level of disruption on the pilot body and my prediction is that there will be an increase in incidents such as runway incursion and excursion, altitude busts and fuel incidents. Lots of pressure from the company and from the home front which is not a good combination. That pressure will be present for the majority of pilots, Captains and F/Os.