I use a shift lens for perspective correction (OM 2.8/35), but if things are not quite perfect, or I have used a different lens, there are good tools in Capture One, where I can process RAW files and makes it almost unnecessary to do any further editing other than panoramic stitching, which I used to do in Photoshop Elements but now do in Affinity, which is much better value for money, even if a little complicated (there are plenty of videos explaining how to do most things).

I use perspective correction in Adobe Raw, and then try to squish it's horizontal/vertical stretch by playing with the aspect ratio.

I use Capture One for post-processing. The versions after 2024 have manual and automatic perspective correction (vertical, horizontal, combined = full rectangular correction). Sometimes it's necessary to correct manually, when it doesn't find the lines or choses the wrong ones (in old towns it might be better to use a tripod and bubble levels first, but I'm lazy).

Sometimes I pine for the old days, using Photoshop Elements. I allowed, among other things, drawing a quadrilateral to define different horizontals for top and bottom, different verticals for left and right.

WalrusTexas:

I think that's how you do it in CaptureOne as well?

timleeuw:

Well, depends on the version, as the newer ones have automatic correction modes. You can go back to selecting verticals, horizontals or rectangles manually, as well as choosing values for vertical and horizontal correction.

richard.kralicek.wien:

Yes but even the automatic modes can independently change those 4 sides if that's where they detect the horizontals and verticals.

I just throw my scans into GIMP and do minor adjustments there (eg. dark point). Not particularly high tech but it's quick and works well for me :)

timleeuw: I'm not sure I understood what you mean: Yes, the software detects those sides automatically and independently from each other, but not always correctly. Years ago it wasn't capable of doing that automatically. When shooting older buildings the algorithm goes wrong more frequently. In case I just restated what you said I apologise for beating a dead horse.

richard.kralicek.wien:

Sorry for not being clear. But I think we both understand what the software does and we are both trying to emphasize different aspects of its functioning :-)

Photoshop > Filter > Lens Correction > Custom > Transform > Vertical Perspective + Horizontal Perspective + Angle & Scale. And if that's not enough, there's always Edit > Perspective Warp.