I think he can still be a great rider. He had some bad luck with mechanicals / bad crashes the last years. But yeah, gone is gone. Nevertheless, he should still be able to win Roubaix , RVV or SanRemo.
Well he has already won Sanremo back in 2020 and although he can win it again, he skip it this year, so it doesn't seem to be a priority for him anymore.
I still think he has everything to win Roubaix as he is very difficult to drop on flat cobbles and has a strong sprint but he has been suffering a lot of bad luck and Van der Poel stepped up his game this year.
As for De Ronde, I honestly would be a bit surprised if he manage to beat Van der Poel or Pogacar in that race. Last year, he was just dropped like a stone as he was in 2021. Remco could also become another rival for Van Aert there as he is planning to ride it next year.
Even though, I am not a fan, I am happy that he managed to win the stage today after so many near misses.