I just did mine today 32 Bit on a SD to 64 on an SSD and it was very fast. I upgraded the bios on the pi via the boot utility. I then installed the 64 bit version via etcher. Rebooted the pi with the ssd attached (no SD). Created a new log in. Downloaded my backup and restored. There are some very good directions in the forums. My only issue had to due with the mariadb where I had to uninstall it and reinstall (lost the history).