Exactly this. So many in house web applications would be better as desktop apps. I've replaced a number of these, essentially data management webapps, with desktop apps over the years. Typically writing them in Java, which despite its detractors can be cross platform and performant if you avoid non-public classes, use the built in cross platform support for things like filenames and know which data structures to use.
And that last thing is where many web devs fail, using inappropriate data structures or algorithms and relying on throwing more resources at the thing to make it work well enough. That's less of an option on a desktop machine where the resources are more constrained. Too many devs I interview seem to have skipped the algorithm part of their education, and don't even know "big O" notatuon.