I had to use Private Spaces with Wi-Fi Direct and also install Brother iPrintScan within it. Could not make it work under normal account with Mullvad and local sharing no matter what I tried. Also tried the USB method and I guess my old model also does not work.
Took a fair amount of time to get it going though. Sadly my AIO also does not work with Arch Linux so going to look to get a newer one (probably not too new) at some point anyways. Works with Linux Mint though.