FTPD should work but its very slow, obviously. Not nearly recommended for transferring games. Maybe small homebrew apps.
And if I'm not mistaken FTPD works only in one direction. PC to Switch maybe. But not Switch to PC, so also not useful for transferring and editing savegames.
There is also a payload that lets you mount the Switch as SD-Reader via USB-C. But you need to launch a separate payload for that, meaning a reboot with dongle. Also not very fast.
link?