The problem is that even if we got everyone who most people want:
J.Garcia
Livramento
Cherki
Reijnders
Rodrigo
Is that amazingly exciting?
Is it KDB, D.Silva, Yaya, Sane standard we once had? Nope.
These players aren’t going to make us match PSG.
All PSG players are quick, fast and technical.
Haaland, Marmoush, Doku won’t close down defenders like they do.
Rodri Reijnders and Nico G are quick around the pitch and as tenacious as Vitinha, Neves and Ruiz.
We all have to face facts that our time of being the best is over for a few years.
This window won’t get us back.
(I can imagine this message won’t impress happy clappers but it’s the truth).
You might be right about it not being a quick fix and we may have a couple of years fighting for the top league positions rather than being way ahead or in a two horse race.
But the argument of "X signing(s) isn't (aren't) as good as Silva, yaya, de bruyne is very disingenuous.
Silva was up and coming and had yet to make his big move when we signed him.
Yaya had been shuffled around positions at Barca and was seen as a solid DM and not the game winner he became for us.
Kdb was player of the season in Germany but not yet seen as world class.
I would argue that reijnders and marmoush are very much at the stage in their career that gundogan and kdb were at when we signed them. Probably less progressed than Silva as he'd had the 2008 and 2010 Sprain tournament wins at that point. But they are the calibre of players we signed previously. Will they be as good? Dunno, but the best signings in the windows of previous seasons were very rarely widely considered to be as good as prime city yaya, kdb, and Silva.
I think Rodrigo is absolutely at a similar career phase to yaya (obviously different positions but leaving Spain's best team to get more game time)
Cherki is a bit of an unknown quantity given the rumours of his enterage and attitude but for the price it's a gamble worth taking given Foden has proven he can pick up the kdb slack over a full season - assuming he sorts his personal problems out over the summer.
It's not as black and white as your post makes it. We missed out on Alexis in 2017 when he was supposed to be our main signing. We already have most of the spine of the team intact with Dias, gvardiol, rodri, Foden, haaland. I could see the signings you listed above just as easily taking us to the title next season just as easily as I can see a couple more seasons in a scrap.