This is my remix of the Ender 3 Side Spool mount. This mount allows you to center the spool on extruder to help prevent any side pulling. I also added two v slot profiles to add rigidity and remove the need for additional fasteners.
Print with atleast 4 walls and 40% infill (this is structural). Supports may be required from build plate for the gusset area. Scaling may be required depending on printer accuracy. Print part on its side.