Brother iPrint&Scan 4+

Firstly, I use PDFScanner app for all my scanning needs and have done for several years with a monochrome brother MFC - worked brilliantly and I loved that I could do duplex scanning. Then my wife decides we need a colour laser so I stick with Brother and buy a MFCL3750 - first Big Sur can't detect my scanner and therefore PDFScanner app can't either. Then I discover there is no duplex scanning on my bigger, flasher and more expensive unit. After serveral hours I discover iPrint&Scan which miraculously allows me to detect my scanner and to scan. I also find I can open my scanned docs in PDF Scanner and process docs just like I always have. So for that reason I am reasonably happy with the app, although I would prefer to be able to just use PDF Scanner directly if anyone from Brother is reading this and can figure out how to enable Big Sur to be compatible with Brother MFC scanners again

Brother support says to install this app to run my printer by USB cable on my late model apple mac OS. So I've done that and all it seems to allow me to do is scan documents. It doesnt allow for my printer to connect for general printing on my mac. To make matters worse, brother support no longer offers drivers for my printer - it just says to install this iPrint app. So I'm left with no idea how to setup my printer. What's going on here?

Ugh... Finally got it working. The WiFi module used in these printers is pretty ordinary...
I set a static IP and it seems to be working ok now.
It might be a better idea to hard wire this printer.. its just a bit too flaky...The app did tell me to check network settings... I was able to ping it then it stopped. The printer itself doesn't give any feedback if its not getting an IP properly.