I'm genuinely not sure that a 'big name' replacement will work. Koeman is one of the biggest names in football, and it's gone tits up.
I think Tuchel is out of the question, he's got Chelsea written all over him when Conte gets binned just after Xmas.
I still think someone who has a link to the club and the players will be a much better option. They're not exciting names but Arteta, Unsworth, Ferguson, Stubbs, Royle could give us that stability back, even if it's just on an interim basis until the Xmas or the end of the season.
If not them then Dyche, maybe Howe or even Allardyce! (I can't belive ive just said fuckin Allardyce)