Buying battle pass on switch and acquiring the rewards on pc.

Right, I play on both switch and PC (which congratulations for being able to do that, you must have nerves of steel, lol) and I do exactly what Midnight was saying.  The apex coins don't transfer so just make sure to check the BP and only complete those levels on the device you plan to accumulate the coins on.  I always roll my 950 coins over to the next pass each season, so I check and if the level that gives AC away is coming up I make sure I'm playing on PC when that happens so I can build my coins up in the PC wallet.  Good luck :)