The coordinates in the address bar are where the map is centered. That happens to be at the business location if you click on the map in the knowledge panel, but if you start moving around the viewport it will change.
As far as accuracy down to the 5th significant digit and small changes, I'll give you my own personal theory. I don't think small mismatches will cause any problems, because I think this number is mainly used as any data point to try and pin down the actual business location, especially in cases where the address might not resolve properly. To that end, I imagine it's a really useful hint whether the actual lat/long gets you square on the front door, or 10 meters inside the building. Just take your numbers, do a quick search, and make sure the pin is pretty close to the right location. I'd love to hear some kind of proof or at least an anecdote if someone thinks I'm wrong, but my two cents is that as long as the lat/long is close enough to look right to you in a quick search, you're close enough. Always do a quick double check, but don't sweat the exact, exact location, anymore than you'd worry about the position of your map pin for your GMB profile down to the 6 inch level.
For what it's worth, clicking on the knowledge panel and taking that number, and then doing a google search for it and looking on the map, looks like it's in the exact same position as the business pin itself.
Now, time for a small history rant. Feel free to skip this, but strange history facts are a little bit of a hobby of mine.
Currently, the meter is defined as the distance light travels in a certain fraction of time. Meaning if we develop a way to take a more accurate measure of the speed of light, it will literally change how long a meter is, which I think is kind of cool.
But the reason I bring that up, two hundred years ago the meter was defined as one ten millionth of the way from the equator to the pole. There's 90 degrees from the equator to the pole, and 10 mil/90 = 1111111.11.., or about 111 km. So changing the ones digit of a set of coordinates will at most move you around 111km (about half that as far north as you are). If your mismatch is a number in the 1st decimal place, you're off by about 10km, the second is about 1km, and so on. Moving up or down one in the 6th digit only bumps you around at most 10cm. That's way higher accuracy than your phone can measure. Your phone's at best only trustworthy around the 4th digit, and think about where Google's gathering a lot of their data.
The discrepancy between the two numbers you got was significant (the difference was about .002, so it was off by about 200 meters) but you can see how if you have differences in the 5th or 6th decimal position, it literally doesn't matter, Google themselves probably don't have trustworthy data at that level of accuracy.
Anyway, for your case, use your first number from the knowledge panel map:
Adding to what James said - the other benefit of using G maps to grab the geo coordinates, it it gives you a double-check chance to be sure your pin is in the correct spot. So many times I see that pin out of place!
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