I don't really know much about your past discussion but the fact that you said Chelsea Champions League was based on luck is actually disrespectful.
We defeated top teams then including Real Madrid and not like luck played everything for us in the final. We lacked the consistency to win the league and Manchester City who is often the most consistent team in the EPL in recent years lift the EPL, while we defeated them deservedly in the Champions league.
Our squad depth then were so great even to our substitute lists, where even a scary starting eleven could be made. This was one glorious season of Chelsea before the fall and we are still trying to bounce back, I guess you might have forgotten how good/excellent Chelsea were before the whole Todd Boehly era, where we are still finding it hard to find our fit again.
Every club have their remarkable seasons and worst ones. But it's how long that the club stays in their poor performance is what matters a lot. Take United for example, they have been battling with getting the right players and coach to fix the club after the departure of Sir, Alex Ferguson.
Chelsea has also passed through similar situation but with the help of Enzo Maresca the club is picking form because he's cooking something secretly.
I don't see Enzo Maresca has being the main reason for this improvement even before he came, towards the ending of the season under Poch we notice improvements and there are tactical decisions he has made that makes me sound like this TBH.
Now we are back at the Champions League, let's see how we compete against the big boys and improve to dominate here again and possibly lifting another Champions League trophy.