that makes litterally zero sense. MTP using DBI works with MacOS.... sometimes. the issue is the same with any MTP enabled device. The issue comes from MacOS, not DBI, not the Switch. The issue in MacOS is that Apple borked the implementation of MTP. Only one app at a time can access the MacOS's stack (or whatever technical jargon is appropriate). Probably other apps such as Finder or anything having permission to access the filesystem (MS Office, browser, or some random MacOS background daemon) often hogs up access to the MTP driver (though not actually using it), preventing an actual MTP client (such as Android File Transfer, or OpenMTP) from using it.
After closing pretty much all apps open on my Mac, I've found that for some weird reason, cycling through USB-C plug sides combination (Switch side / computer side: A/A, A/B, B/A, B/B) and even changing the USB-C port on the Mac computer usually ends up getting MTP to work (I use OpenMTP).
When it doesn't, a reboot of the Mac is required.
Yes it's a clusterfuck of a situation. And it's been that way for years.