GIMP: creating an xcf image from a jpg photo, creating an empty transparent layer. How to do everything from cli?

Question

bash

Even if you hit the wall, the Internet is full of guides on how to get jpg from xcf, but no one can clearly say how to get xcf from jpg. It seems that creating a file is not difficult, but when creating it, you need to have many parameters: resolution, gamut (sRGB or another) and even orientation (on different devices, forography is encoded as they want - for some from bottom to top, for others - from right to left). When opening a jpg-file, GIMP takes all this into account. And if you get everything and then set it manually, the script for rendering the flight to the moon will be easier.
I feel that there are only 3 lines of code, but I'm already tired of searching - everywhere they advise the opposite things (xcf -> jpg).
Are there people here who have written scripts for GIMP?