Have you tried to hold down Shift key when booting the system?
Then in the grub menu - press C to access console - which has more options than the rescue console.
You cannot target anything inside the encrypted container - unless you unlock it.
I am confused - the listing - this is from running your installed Manjaro?
If it is - then grub is working - and then I don’t understand why you keep saying the thing with grub rescue and why is there a Windows Boot Manager when you say it came without operating system?
I found a similar issue also with Acer Installing Manjaro and PopOs in Dual Boot with windows in Acer laptop breaks BIOS
It also looks like you have an EFI usb stick entry.