"Share Disk" MacBook doesn't appear in "Network" section of the other Mac

One of my laptops (MacBook pro with apple silicon) went kaput recently, and I'm trying to back up the files before I reinstall the OS. I can get it to enter disk sharing mode, but I can't get it to show up in the finder of the other mac (2019 MacBook Pro). The "Network" folder is just empty. I've tried checking finder settings to make sure network stuff is visible, but no dice. And the plist files discussed in https://apple.stackexchange.com/questions/148649/shared-devices-not-appearing-in-network don't seem to exist on my version of macOS. I have the same problem when connecting to my partner's *really* old mac laptop (like 8 years old), but I was briefly able to connect via someone else's mac (don't know what version it was, didn't have time to go into depth or do a proper backup and now they're not around) and access files on my broken computer, so I think the issue exists with the other computers? What I'm trying to do is [Transfer files between a Mac with Apple silicon and another Mac](https://support.apple.com/guide/mac-help/transfer-files-a-mac-apple-silicon-mchlb37e8ca7/mac) .