I think we got better up the wings by turning Digne into Myko and Patterson.
We never had a choice on Richarlison. If you want to argue that we did a poor job of prepping for that eventuality, by shoving the chips all-in on getting to Europe in Carlo's second season in a way that left us with no funds the following season to make another run at Europe or replace Richarlison, you have a leg to stand on. It's not like Moshiri et al were unaware what COVID was going to do to the finances, because it already had landed.
Will selling Gordon improve us? It depends on how we reinvest. If we turn the proceeds into some wing creativity, a creditable striker and another quality mid, we should get better. If we don't, we won't. What's clear right now is that we're too reliant on a single, injured player to produce goal threat, and I would argue that we would be better off if we could turn one of our brighter talents into multiple avenues to get the ball into dangerous areas and into the back of the net.