Slower shifting troubleshooting
Is the question about chainring shifting, or rear cog shifting?
On the chainring shifts, is it shifting to the large ring that's lagging? The shift to the small ring should drop right in.
It might need just a small derailleur adjustment, even though you recently had it done. (Fine tuning a derailleur cable is a good skill to have. You don't need to take it in to get it perfect. It's not hard to learn. Setting up a new derailleur from scratch is more complicated, with limit screws, etc.)
Or a new shifter cable with new housing. But I think it's rare for a front cable to need replacing. The rear cable is shifted way more often, and wears out, and frays from bending within the shifter.
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Chainring wear
They look fine. The anodizing wears off quickly, and the teeth are machined in different profiles for quick shifting.
I posted this in a previous thread:
My Ultegra 11 speed chainrings after about 5000 miles. This is minimal wear. (I'm now well over 20,000 miles, and the rings are still good.)
Note, this is a photo of the inward side of the chainrings. The chain is pulled against the left side of the teeth, and the chain is traveling counter clockwise. An outside photo, like yours, is the opposite.
The threads:
Shark tooth?
Chainring wear check
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