Infinitely better? Marcos Alonso is not an upgrade. You guys complain about Dybala being unavailable, but I am sure you will enjoy Jogba's availability, antics and disappearing acts. I never liked Fagjinho.
De Ligt for Rudiger is a downgrade. Like I said, the only exciting signing on that list is Zaniolo, and he's not exactly robust.
Marcos Alonso is nothing special but he's solid, better than AS or Pellegrini for sure. He would be a short term move while we sell one of the other two, preferably AS. We can't fix the whole team in one summer.
Pogba is a gamble but for the right price I would take it. When he's off we have Fagioli to step in

or even Loca while Rovella plays behind.
Fagjinho alone would make a huge difference. A real regista. Might almost be a Pirloesque signing.
De Ligt is the sacrifice we may have to make to let it all happen without a big drop in quality.
Zaniolo is also a risk but at least there will be Raspadori and Chiesa as alternatives.
Much better starting lineup than we have now plus a deeper midfield.
And the fullback positions. We need young athletic players on the flanks, not two fullbacks in their 30s.
I would argue that strengthening our fullback positions is every bit as important as strengthening our midfield.
I guess Danilo/Cuadrado would suffice on the right for another year atleast but the left side requires a young speedy fullback, not Alonso.
As for the midfield, Jorginho and Pogba in one summer seems way too unrealistic anyway.
1 LB, 1 CM and 1 CB. That should be priority. Then we can make additional filler signings if required.
Pogba may be doable if Dybala leaves.
I could see Chelsea being ready to cash out on Jorginho