[Update 2: The latest version of printer-driver-brlaser works without issue now in Bookworm post release and Trixie (Testing), which both at version 6.3 at the time of writing. Bullseye still has 6.1, so the issue may remain.]
[Update: Unfortunately printer-driver-brlaser is affected by a bug that means documents with images sometimes fail to print with no error message at all. Gnome says the document has printed successfully, CUPS says the document has printed successfully, but nothing appears from the printer, not even blank pages, and the printer records no error.
Back to the driver from the Brother web site then.
See Google Groups, and Github. The driver is patched on Github but it seems there is no Debian maintainer for the package, so no hope for the moment that the Debian package affected (6.2) will be fixed any time soon.]
The Brother HL-1212 WiFi printer does not do driverless printing. See previous post. "Modern" printers don't need drivers, but budget printers like this one (still on sale at the time of writing) seem to date back a decade or two and need drivers.
Previously, I downloaded a driver installation tool from Brother (which worked very well). I am now using Debian Bookworm (Testing), and found today that Debian has included a driver for this printer it its repositories in Bullseye, namely in:
Adding the printer was a very easy process. In the printer dialogue click "Add". The printer dialogue found the printer without adding the network address, although there is an option to search by IP address. Three options came up - the printer name, the printer name with some sort of address I didn't recognise appended to it, and a CUPS reference. I chose the first one and the printer entry that came up printed a test page straight away. (Gnome Software said it needed to look for additional things to install, went away and did so, and came back to say it couldn't find anything, but the printer worked anyway.)
The printer entry contained fields for driver and address, so I selected/entered those, even though the printer seemed to work OK already.