I'm glad you mentioned photography - I am a pro Photographer as well and am interested in moving to an iPad as my main editing machine, at least to take a lot of work off my desktop. The Pencil is intriguing and it is certainly lighter weight and has a better quality display than any laptop I have found. But it seems that pretty much the only DAM that you can use on iPads that is useful for pro work is Lightroom (not that there are many other great choices on macOS or Windows to be fair). Lightroom is fine, but what if you want to open a Lightroom image on your iPad in Photoshop and make further edits, then have that edited image appear back in Lightroom - is that possible as it is on macOS? I also can't find a soft proofing mode to prepare images for print, export with (or without) watermark to a folder or ZIP archive for emailing at reduced JPEG dimensions and quality. Does Lightroom on iPad support tethering like the macOS version does? Granted a lot of these features may exist I just haven't found them in my cursory examination with an older iPad. And perhaps there is a better DAM for iPadOS with these features - please let me know if that is the case?
You can’t proof for print with Lr on the iPad, but then you cant print from an iPad anyway. Anyone serious about printing has serious printers which won’t work on an iPad. That’s certainly a limitation but also fairly niche.
You can round trip between Lr and ps on the iPad.
If you want to work with lightroom classic then it just syncs. If (like me) you don’t want to push all your raws to the cloud and back again, I just use it with sync paused. I then export the edits as dng which includes the xml sidecar. There is a limitation with this though- it’s only readable by Adobe stuff. So Lr, ps etc across mobile and mac/pc. It’s annoying, If you want to use AP or another non Adobe app then you can export it as a tif. This won’t keep the file editable in LR though. That said if your wanting it so you can edit it in AP or something, then that would be the same in lightroom classic. Although classic is way better at handling this creating stacked versions etc.
Adobe is ruining lightroom with this push to the cloud for everything. They should just release a suitable version of classic for the iPad. But they won’t.
There are export options, including water making etc.
Also you can just use your iPad as an editing surface for lightroom classic, which make it infinitely better for editing anyway. It’s what I do some of the time with my desktop.
For calibration I have my benq monitor which is calibrated, I check my work on there if I have been away - I have never needed to re edit. If I’m at home then I mirror as I’m working. Lr mobile allows a full screen proper second display.
Lightroom mobile doesn’t support tethering. It’s a little annoying but then you can use Cascable to tether. It’s more ‘roundabout’ but works well.