Basic Information:
Printer Model: custom (cr10 copy)
MCU / Printerboard:BTT e3 mini v3
klippy.log
New install on new printer, 64 bit rasp pi and klipperscreen.
Pi/Klipper will not connect to mcu via usb. I an using 64 bit Pi-os
Describe your issue:
…
Without the requested klippy.log helping you is quite hard.
Please attach it to your initial post or new post.
If it is too big just zip it.
Edit: Looks like your Facebook post got the helping answers already: install 32 bit OS.
But please for future issues attach the klippy.log! 
NAPCAL
3
If you are running Debian Linux an update broke the by-id links that you would use for USB.
Do this command to see if you are running Debian
cat /etc/os-release
If so then this link will fix this problem.