I've been replaying Halo Reach after playing Halo Infinite and one thing has been bugging me while replaying it. The game seems to imply that everything prior to the end of Long Night of Solace was done with the expectation that the Covenant could be countered and driven away from Reach. There is little to no mention of it all being delaying actions to support evacuations until Exodus and then characters will talk about Jorge's death as if he actually believed he had just saved Reach.

But considering the capabilities of the Covenant this seems completely nonsensical, you could make the argument that they could have nipped it in the bud during the mission Winter Contingency if the Covenant force was just a small scouting group but Sword Basen and nightfall show concentrations of Covenant and ships to a point where it would be safe to assume that they had reported back to the rest of the Covenant. By Long Night of Solace it seems absurd that anyone, especially Jorge, could believe that destroying a single Supercarrier would save the colony.

Once the Covenant realised the size of Human presence on Reach that they would respond with a fleet as vast as the Fleet of Particular Justice to which Humanity was not going to be able to fight off over Reach.

Am I misunderstanding some dialogue in Halo Reach? Is it just Reach's writing being a bit wonky? Or am I missing something that would give the UNSC a realistic chance of success?

Edit: thank you for all of the responses!