I agree that he should be stronger in 2023, which is a frightful prospect for the competition, however, it's also true that the best laid plans don't always come to fruition. He could crash or get sick at the wrong time or the even higher expectations in Belgium could weigh upon him psychologically (he himself gave a hint of this by recently saying "people need to understand I can't win all the races"). Of course, with only four events before the Giro he might be understandably insincere, but the statement shows he is aware folks just expect success from him, but even he is only human after all. Look at what happened to Pogacar last year, everyone thought a third consecutive Tour victory was a foregone conclusion, but then he unexpectedly met his match.
And the Giro will be a different beast than the Vuelta. It will be much colder and the amount of climbing, the length and altitudine of the climbs in the third week will be something he hasn't tackled before racing. And, if Roglic, Thomas and Vlasov are in top shape, the competition will likely be tougher than at last year's Vuelta. Of course the same is true for the others facing a smashing Evenepoel. But I go by the philosophy of don't count your chickens before they are hatched. Remco wisely, at least publicly, seems to agree, saying he is going for a couple of stage victories and a top 5 GC, adding that he'd be satisfied with a podium like a victory. Of course, privately he may only be happy with overall victory and doubtless it is within his reach, but just say Roglic is really super too? It would be a great battle and Remco could not afford to go down as at the Vuelta and then ship time to Primoz in the next mountain stages.
Sure there is every reason to be optimistic, even confident, about his chances for victory, but in cycling there are so many variables that make execution of the plan not always easy or possible. If anything, Liege should give a pretty clear indication of what Evenepoel will show up at la grande partenza. And then from there it all has to go according to plan or, at any rate, with the least mistakes and bad luck possible.