P: (AI) Upright mode for framed artworks, documents etc.

Agreed.

Guided mode takes a lot of time if you need to correct several hundreds of photos with paintings on the wall or photographed documents etc. Even using shortcuts.

Have you tried Transform > Guided?  You have to set the four guidelines manually, but the results are very good.

Unfortunately Full mode does the job randomly. I tried it several times and it needs to be carefully checked, so now it's faster to correct a batch of images in manual mode. That's why the special mode for frames and artworks will be great.

I find that Full mode does typically work well for this purpose, but only provided a contrasting background (against which the artwork has been photographed) is relatively plain and featureless. Because besides ignoring content within the artwork's edges, it may also be important to ignore context outside its edges.

Guided upright is of course a very successful intervention, in cases where auto detection has missed (this must sometimes be expected).