You're deliberately pretending that Amad and Garnacho are our only wide players when you know it's not true. Rashford, Garncho, Amad, Antony is 4 wingers for 2 positions, it's absolutely standard in terms of numbers. And the likes of Mount can also cover there.
Sancho is a non-entity that doesn't actually need replacing. He barely played a game for us last season and we sent him to Germany without a replacement.
We already have Rashford stealing Garnacho's minutes in the first 3 games of the season. We don't need another old past it player further reducing his minutes.
Now, if you're telling me we could replace Sancho with someone who is actually good enough, or has huge potential, then fair enough, we'd actually benefit from that. I don't see the need for us to go from 4 players who aren't good enough to 5 players who aren't good enough.
What exactly has Sterling shown Chelsea's squad about going the distance in the last 2 seasons? This is not 2019 Sterling, and we are not Manchester City. He'll be even worse for us than he's been for Chelsea given we'll get an even older and slower version of him.