i currently own 3 pairs of joy-cons. the first is a Red/Blue set that came with console, which did initially have some sync issues, but after a controller update, they worked a lot better. i dont usually sit that far away from my Switch, so thats another thing. my second set is Grey and required a controller update as soon i bought them. they desync a bit when sitting further away, but it could also be from obstructions. my third and final pair is the Splatoon Pink/Green set which i havent had any real problems with.
another thing of note is that the issues could stem from the bluetooth receiver inside of the Switch itself, although i dont know too much about how bluetooth works so dont quote me on that