If the route is US-69 all the way to KC, it is not a route to take if you are in a hurry. Smaller cities will also slow you down, and speed limits sometimes remain low for a few miles into what looks like rural areas, where people speed back up to 65 and get caught for 20 or 30 over the limit. Atoka catches a few people, but it is not the only city gleaning revenue from people in a hurry.
Because I'm usually going through Tulsa from Dallas, I don't go any further north than the junction with the Indian Nation Turnpike, but I have traveled 69 all the way to Kansas City, and for KC as a destination I would rather go up US-169 (bypasses more of the towns) or US-71 (four-lane divided most of the way from I-44 north).
On US-69 getting through Muskogee can be slow, Wagoner WILL BE slow, Vinita and Miami are slow for a short distance, Pittsburg is slow and congested, Fort Scott is slow, and you get into suburban traffic about 20 miles out of KC.
Something in your mapping program is missing information about local driving conditions.