BLTouch Z offset needs changes
I can't really follow the information provided but I've read that Creality had some issues with saving settings if there was no SD-card in the printer when saving, could this be the issue?
I would recommend trying another firmware (not from Creality but something like Smith3D.com (https://smith3d.com/ender-3-v2-bltouch-firmware-installation-guide-by-smith3d-com/) which I've used before with success.
If you're willing to pay for precompiled firmware (and support the Marlin developers) I can also recommend https://marlin.crc.id.au/ (which I use now)