The only problem I see with this statement is a soft cap is not possible when the switch is running a completely different operating system apart from the traditional boot loader. It's also been mentioned here the issue is with the eMMC speeds of the flash controller:
https://gbatemp.net/threads/looks-l...-50mb-s-both-wired-and-wireless.463324/page-5
This means, you will be getting, most likely, WORSE speeds dumping to an SD card as that is now bottlenecking at the card controller / flash chip.
In other words, network dump is your best bet.