I have several bikes with STI shifters, going back to the dawn of brifters: circa early 90’s. When you are the 'bike guy' at work, bikes and components tend to fall into your lap.
I actually far prefer Campagnolo Ergopower ergonomics, but leave this aside.
The best shifting (fast, trouble-free and precise) out of all the STI shifters: the ones with the shift cables on the outside. The recent move to under the bar shift cables introduced tight bends, and extra friction. Plus the propensity to eat cables.
I have some mid-90s Shimano 600 shifters: pure shifting bliss. Flawless. Shimano got brifters right - right out of the gate.
You'll get some howls of protest... how can 25-year led shifters be any good... the reason why most folks give up on old shifters is because a cable end is jammed in a shifter body. Or their cables and housings are worn, and should have been replaced (yearly). Or their old shifters could have been revived with a 5 second spritz of WD40.
All simple and cheap fixes.