They most likely are, especially given that Santi Aouna of Foot Mercato has been pushing United's name himself in his articles.
With that said, United's activity in the winter transfer window seems to indicate that Poch is most likely at the top of the shortlist. Wherever Poch has been, he's disliked teams bringing in players without his input and final approval, and more often than not, he'd either not/barely use the players who were brought in without his input (Janssen at Spurs) or use them in an unexpected manner (Danilo at PSG).
I think we'd have made moves for incoming signings if we prioritised any of ten Hag, Lopetegui, Rodgers, Amorim, or Rangnick over Poch. The aforementioned managers tend to be more willing to work with the players at their disposal rather than demand for very particular players. Overall, Poch is more like Conte in that regard.