I have designed a 45 degree mount for the wired doorbell and posted it on Thingiverse if anybody wants to 3d print it. Eufy wired doorbell 45 degree mount by Leighbus - Thingiverse
It uses both sets of screws that come with the doorbell, the long screws to fix the mount to the wall then use the short screws to fix the doorbell backing plate to the mount.