That is what you would expect for shade. For deep shade, I would overseed fine fescue mix. Make sure you reduce your fertilizer input in shady areas and mow high.

Thank you mishmosh!

The longer the grass the more light the blades will absorb, so I would also try 3-4" or max height but that would require a rotary mower. Keep the leaves off. Looks great!

You are watering too much and too frequently.

Watering: Deep and infrequent is the mantra for watering. This is for all turf grass all over the place. Deep means 1 inch all at one time. Put some cat food or tuna cans around the yard, and time how long it takes your sprinkler(s) to fill all the cans. Memorize that time. That will be the time you water from now on. My hose, sprinkler and water pressure takes 8 full hours to fill the cans. Your time will likely be less. I like gentle watering. As for watering frequency, that depends on the daytime air temperature. With temps in the 90s, deep water once per week. With temps in the 80s, deep water once every 2 weeks. With temps in the 70s, deep water once every 3 weeks. With temps below 70, deep water once a month. Note that you have to keep up with quickly changing temps in the spring and fall. This deep and infrequent schedule works in Phoenix and in Vermont, so it should work for you. The reason for deep and infrequent is to grow deeper, more drought resistant roots and to allow the soil to dry completely at the surface for several days before watering again. If it rains, reset your calendar to account for the rainfall.

Thank you guys! Also would KBG grow well in shade?

No. I'd be surprised if you didn't have some KBG already in the lawn, which is why it isn't doing so well. Your pictures do not look like tall fescue.