LR Classic underperforming against CC and ACR

Say it is a 'small' LR Classic catalog, 1000 images. How well would Photoshop and ACR manage with opening up 1000 images together, so that they were all immediately available for editing, and for on-the-fly output, working either in batches or individually? Just making sure we are comparing like with like.

tl:dr; Horses for Courses.

Each of these two solutions, is focused on a radically different conception of workflow. Each one can therefore be expected to be less good, at carrying out the other one's characteristic workflow tasks. Because it is designed around its own natural working methods. For example: some people try to treat LrC as if it were a conventional file-based image manager, with lots of importing and removing and folder syncing, perhaps multiple catalogs and moving files around, and tend to find the whole experience correspondingly clunky and awkward. Using LrC more in the way intended, tends to require some careful UN-learning (the need for this is all the more difficult to grasp and accept, the more experience you have with conventional workflow) but that un-learning truly is the road to an easier, more efficient and less frustrating outcome.

Underperforming? In what way? Be specific. Also please state the following details.

Also, catalog size usually doesn't cause performance problems.