I already got mine fixed by Nintendo. And yeah, it's better, but I'm still having problems.
Before repair the left joy-con was almost unusable and would desync even 1 meter away from the console. Now, the left joy-con seems fine, but sitting at normal distance from my TV (3-4) meters, with clear line of sight between the joy-cons and the console, sometimes the buttons on the RIGHT joy-con stop responding for a few seconds.
It seems to only happen if the switch is docked.
Bottom line, signal is still crappy. Pro controller has no issues whatsoever and I have been playing with that for 20+ hours without a single hickup.
Ive emailed the local Nintendo distributor again to see if they can do anything about the right joy-con.
Oh, and I also bought a second set of joy-cons. Same goddamn problem.