While I agree that it's very disappointing we didn't get another attacker in this window, I'm going to reserve judgment on if it's a failure or not for the summer. We simply cannot mess about this summer - we need to execute quickly and decisively to address 3 positions (at the bare minimum). Thankfully it seems like we have already done extensive groundwork on two of them but that will be all for naught if we don't get them over the line.
CM replacement for Jorginho/Partey - Zubimendi
World Class CF (or at least potentially world class CF) - Isak/Sesko
Starting quality Winger - Williams/Barcola/Semenyo
I think we should look to wrap Zubimendi as close to the start of the window as possible. Isak's pursuit should be dependent on if Newcastle gets Champions League or not - if they do, then pivot immediately to Sesko and get that over the line ASAP. Then I think our winger chase can be more reactive depending on who is available but my preference is probably Semenyo unless we know Barcola can be pried away. If we came out of the window with, at minimum, Zubimendi/Sesko/Semenyo, then I would judge it as a success. They may not be the biggest names and there is certainly some risk with Sesko but you've got two very solid players in Zubimendi and Semenyo (who I think has another level to his game) and a gamble on the ceiling of Sesko. I'd assume we would also go for a backup GK like Garcia and depending on defender movement, potentially a younger defender like Hato as well. But we need to nail those first three signings or we will have failed IMO.