brent simple-scan NEVER works for me but there are others
While it doesn't help you since you are using a Canon, in the case of @Axios there is a simple-scan update I'll be putting into the stable repo during the next sync that will at the very least fix size detection for Brother scanners.
I will say that no matter what printer / scanner combo I have tried or heard about, they all can be a PITA and vary in whether or not they function from update to update (for example, hplip might fix someone's printer but break someone else's, it's a no-win scenario). Printers / scanners under Linux just straight up suck. The closest we got to things working magically was with Google Cloud Printing and they cancelled that, soooo RIP.
I've been fortunate enough to have my Canon printer / scanner work after lots of trouble with CUPS, manually copying over various canon utilities, etc. On vacation I had success with hplip on a family member's scanner. In terms of Brother printers though, there is a reason we have a task that dates back to 2016 that has about a billion links to random printers and it all eventually fizzling out because folks like @Girtablulu rightfully got tired of chucking eopkgs at folks. In terms of Brother printers, their support is just complete garbage fire.