I think that from 2015 to 2018, Dybala was probably the best player in Italy (although many would argue). The goals he scored in those 3 seasons were legendary and he was our main creative spark too. Having prime Dybala in our team was a key reason for our domestic dominance, I lost count of how many times he made the difference in Serie A.
Tuz would have appreciated Dybala a lot more if we weren't so obsessed with the Champions League around that time, instead of just appreciating what we did have (a great team that won the Scudetto and Coppa every season). Instead everyone was frustrated that we couldn't win the UCL and just vented their anger on whatever scapegoat they could find.
But in the end, playing through a hamstring injury against Lyon in 2020 ruined him for good. He was never the same physically after that, so we did make the right choice by selling him. Where we messed up is that we never truly replaced him (Di Maria doesn't count). Our attack has been so predictable and one-dimensional ever since Dybala declined/left.