What am I looking for? A skill, a grinder, or a coffee?

My wife and I have been pulling shots for lattes and cortados about 10 years now. Started with a Breville infuser and bodum grinder. Stepped up to a Sette 270 after about 2 years. Then at 5 years we graduated machines to a Profitec Pro 700. Around the same time we added a Niche Zero alongside the Sette for pourover and decaf single dosing. Eventually we just turned the Niche into our daily grinder for everything. We have gotten to the point of where we feel like we are wanting more from our coffee; more nuance or something that we get from our good local coffee shops when we stop in, but we can't reproduce at home.

We have tried getting bags of what the shops are brewing and dialing them in at home. The ratios and timing that the shop tells us get dialed in well and repeatable, but there just doesn't seem like there is anything exciting in the cup. Tried some Proud Mary light roasts, everything got lost in the milk to where it just tasted like steamed milk in a cup with leftover coffee. Tried some Dark Matter and Andytown medium roasts, Mayorgas, Toby's Estate. Medium roasts just come out generic, but at least they have a flavor. So we've been riding the same medium roast for about 7 years now, consistently enjoyable for us, but we would like to get outside of our lines a bit more and experience at home what we experience in shops.

I know for a fact I'm not looking for a new machine. I'm trying to convince myself that I'm not in need of a flat burr grinder, because I'm trying to actively block an upgrade syndrome. So that leaves me to only criticize my technique. Perhaps there is more to hitting the checkboxes and adjusting accordingly, but I have no problem dialing a bag in for 18g:36-42g in 27-36 seconds. We use custom water, WDT, and controlled tamping. So perhaps I'm missing something in the nooks and crannies of technique.

What change did you do one day that you look back on and can point to as the moment your home espresso took a leap?

Or... do I need to get flat burr grinder and go explore; is there enough opportunity there to get us where we want to go?

Thanks to anyone who takes their time to respond.