Leclerc and Sainz fell from fourth and fifth on the Silverstone grid to finish ninth and 10th, with both losing out from a mid-race safety car that compromised strategy and left them on weaker hard tyres.
Despite ongoing criticism of Ferrari's strategy, Sainz defended what he reckoned to be a "50-50" call and instead laid blame with the inconsistent nature of the car that was exacerbated by strong winds.
These unsettled the car, with 2022 British GP winner Sainz supposing his laps could vary by 0.4s depending on gusts as the SF-23 proved unpredictable despite the team having sported a revised floor for the Miami GP as part of an upgrade run that was conceived to make the car more benign.
Sainz explained: "Very windy, very tricky car to drive again, very difficult to be consistent in these conditions… We were certainly struggling a lot on traction in all the tailwind.
"We couldn't get on the power and also a harder tyre made the fighting and everything very tricky.
"We know it's our weakness, we know where it is. We see it in the wind tunnel, we see it in our car, we see it on the driving, on the feeling. So, it's just a matter of developing.
"At least we've done some progress still. But again, Silverstone has put us back in a position where we know we need to improve the car."
This susceptibility to varying conditions will leave Ferrari "exposed" at different circuit types.
Sainz continued: "It's not a great thing for us because we are very dependent on the wind and the track conditions and on the track temperature for our own performance, which will leave us a bit exposed to some weekends.
"Clearly the tyre [degradation], the tyre energies, the wind sensitivities, the unpredictability of the car, one lap I was 0.3s or 0.4s quicker than others just because of a gust of wind, so we still need to focus on that."
Leclerc added that the car, deficient in high-speed corners, could become "extremely difficult" when operating out of its sweet spot.
He said: "There's still a long way to go because at the moment, we seem still very sensitive to the change of conditions.
"When I say change of conditions, I mean mostly the wind. When we have a change of wind our car becomes extremely difficult.
"On that, we have made steps forward but there is still quite big steps to do.
"We knew this track was going to be one of our worst tracks. Just because of the high-speed corners, this is one of the weaknesses of the car.
"I believe we know why we are struggling. It's clear for us we are pushing a lot on the development, especially for the high-speed corners."
