If you’re just looking to widen the gap try
a) shims/spacers
b) beefcaking it. (2 bearings in the gap)
Or you might be able to find the bearing outside of yoyo stores. Although the width of an A sized bearing and a C sized bearing is less than a millimeter difference. (.157" vs .187")
look for a 5x10x5mm bearing. It’ll be the same diameter as the A size, but 1mm wider.
First off, try cleaning the bearing. The responsiveness of a yoyo is primarily controlled by the condition of the bearing. Next, remove only one sticker. removing both will make it play horribly.
If all of that fails, dynikus’ suggestions are the most reliable next thing to try.