Well I just could not find this plate stl model with real dimensions for some time on internet.
I finally disassembled my printer and took dimensions from that part. It's really helpful during designing anything related to this part. I hope that I took those dimensions right.
I hope you will find that useful.
Updated
2021-01-26 I did update some of dimensions to make this more precise.
Ender_3_V2_back_plate_V3.stl | 666.9KB | |
Ender_3_V2_HotEnd_Plate_V3.rsdoc | 357.8KB |