One strange puzzle...….
I have been using Cura 3.4.1
So, when I "add a printer" to Cura, the printer list under "Other" does not have Ender3. Creality CR-10 is on the list, but no Ender 3.
I manually entered Creality 3D Ender 3, and when I opened Cura and selected Ender 3, the "bed" diagram was...