Hi Sumit,
To remove those double lines, is done by Merging Vertices that are close to each other, but we have to be careful, not to remove too many. After some testing, I believe that the following Value for the Treshold Distance works. First, Select the A and B butoons only (ALT+A to Deselect everything, and then you can hover over the buttons (one by one, of course) and press L.) then : M > Merge > By Distance and adjust the Distance to 0.007:
