It happened again to manjaro-xfce-22.1.3.
Again grub rescue was useless as none of the partitions had a linux file system.
The same happened to a flash drive with linux on it. However, with the flash drive, was able to repair the boot-efi partition as a linux file system was still present.
Not sure why /dev/sda1 had no linux file system to allow repair.
Fortunately, was able to restore the boot-efi partition on /dev/sda1 from a Clonezilla image.
Have dual boot Manjaro/Win10 on a laptop but never had this problem.
But that Win10 installation is from an earlier release where it was still possible to disable Win Update.
This Win10 installation is from Win10_22H2_English_x64v1.iso
Will now have to disable UEFI in BIOS to see if that is a solution.