There is a big difference to replacing carrier based Skyhawks with carrier based Super Etendards and tripling the number of medium range Canberra bombers and fitting them with an anti ship radar and missile system that no one had every done before.
This I’m afraid is total fiction. The Sea Harriers smashed a Canberra formation early on in the war, no reason why they wouldn’t do the same to Canberras carrying Exocets. As to the cover by Mirages this is easier said than done. Two aircraft with very different flight profiles can’t efficiently fly a single formation certainly not a long range one. The Mirages lacked the range to go all the way to an Exocet launch point into the task force anyway. Plus the Mirages basically failed to deter the SHARs without having to worry about escorting Canberras so I don’t see how they would make much of a difference.
As to not intercepting any Super Etendards this was because of incompetent intervention by the STAVO into the Air Defence Commander’s operations. A SHAR CAP was positioned right above the second Super Etendard sortie flight path (first sortie to attempt an attack and the one that sunk HMS Sheffield) and ESM warning provided for the Agave radar (from the first Super Etendard pop up about level with the longitude of the Falklands). Despite all this and a second SHAR CAP to the north being redied for a slashing support attack (as was the strategy) the STAVO intervened and ordered the CAP SHARs to descend to sea level and fly away on visual ocean surveillance (he didn’t think the radar worked) missions (to make sure no Argentine battleships were sneaking up on the carriers). Without this intervention the Super Etendards would have been shot down.
The third Super Etendard sortie (that sunk Atlantic Conveyor) was plotted way to the north to dog leg around the task force’s CAP. The third was a strange mixed event with FAA Skyhawks that just bounced a frigate group south of the Falklands. Super Etendard missions were flown at very low altitude to avoid radar detection. The Canberras would have needed to fly higher to make it all the way to the task force without IFR. There is little chance they could have got through the CAP. With a massive 18-24 plane package being assembled and launched the task force would have had an intel warning and could have launched the warning fighters to double the CAP. Other SHARs would have come running from everywhere to get in on the trade.
I have seen some comments from you that are not exact:
-you say the Royal Navy commanders planned badly some Harrier caps which ended in Argentinian jets achieve the ships, but once Argentinian detect/guess a ship and can pass onto comrades, many sorties are done to distract, confuse, run out and eliminate the Harrier caps, so that some Argentinian jets can achieve to reach the targets. So i would not say, in general, there was a bad commanding from Royal Navy in the caps, you see simple that some jets get to the ships but many times is a intelligent global effort from the Argentinos to "mission kill" the Harrier caps before other Argentinos get to the ships.
-you say, either the "Argentine pilots were terrible, or the Harriers were much superior jets", because you say Argentine didn´t score a single Harrier kill. But there are many factors that you don´t mention, like the radar superiority from the Royal Navy ships, to direct and help the Harriers. Argentine radar in the Falklands just reach 50 kms over the sea, so it was useless out of that range, similarly was a radar with little discrimination of number of jets in the screen. Argentinian jets didn´t have nothing but their sight to beware of Harriers, different to Harriers that knew before where the
Argentine jets were. The Argentine jets didn´t have navigation system, just one out of 4 or 5 jets did, so that they had to be joined in the mission, with very little flexibility to do independet engagements, independent of the navigation jet of each group. Recall that the Falklands are 800-1000 kms from Argentinian bases, in general they just had 10 minutes to be on station before going back. Argentinian didn´t have reliable missiles, as the first time they had a Harrier in the lock, they launched the missile and it missed the Harrier. Old Shafir is not the same as newer version os Shafir. But i´ll read more on this to post something better. Also the guns in the Argentinian jets stoped easily and some of them didnt shot more than 5 guns before stoping. Also Argentinian jets didn´t have tracing munition for their jets gun, so that able to correct the shot. And finally and so important you can´t weight an engagement fairly if ones come from a relaxed cap, and the Argetinian come from a fligh at 15 mts high from sea level, at 900 kms/h, after dwelling with some ships 20 mm, 30 mm, missiles, during 2 minutes, in general. And you shouldn´t expect any Argentinian jet in such a situation is going to want to engage with Harriers knowing all these conditions and the Sidewinder.
-and i want to make Argentinian heroes their pilots, not "terrible pilots" but "incredibly skilled pilots". If you have seen how Sky Walker in Star Wars destroyed the Death star with an heroic effort, the argentinians did the same but many many times.