How to reverse selected pages only

I know there are solution to reverse all pages within a PDF file.

I have been scanning documents and need to reverse  a (large) number of pages within the document.
Grabbing / moving them one by one is quite a workload. I wish I could select a number pages, say 10 pages or so, have them reverse sorted and have them move to the right position.

Probably impossible, but nonetheless asking.

'Nothing ventured, nothing gained'.

This probably is just a one-off thing, it makes no sense to resort to paid solutions.

Any suggestions?
Thanks.