I agree with Mal Grey. If you are backpacking then you have maximum choice for the wilder areas, and can combine coastal and hill scenery. "pretty much anywhere on the west coast north of the Great Glen" sums it up really.
If you are a photographer, then the Loch Maree / Torridon area (including the less famous Coulin Forest, immediately to the south of Glen Torridon), the Fisherfield area, and the Ullapool / Coigach / Assynt area are, for me, outstandingly scenic. Personally, I find Skye unquestionably dramatic, but not as compelling scenically, perhaps because there are fewer trees. Areas such as Loch Maree and Glen Affric where there are remnants of the Caledonian Forest are especial favourites of mine. But other WH members wil have their own favourite areas, all of them equally good in different ways!
For an example of a backpacking/bothying tour by another WH member, see h
ttps://www.walkhighlands.co.uk/Forum/viewtopic.php?f=9&t=53532I agree with the advice to pick two or three areas and enjoy them thoroughly, rather than trying to do too much.
You will be backpacking during the stalking season. So be aware of this
https://www.walkhighlands.co.uk/news/stalking-information-on-walkhighlands-for-new-season/0016741/In my experience you are usually fine if to keep to the ridgelines and avoid corries. Many paths do this anyway.
Also take midge repellent!
Tim