I don’t know what your caching settings are, but my users download the app exactly once, and then only again if I push any update (or their browser cache randomly decides to clear itself, don’t really have any control over that).

Aside from that, they use the app literally their entire workday, so spending 5 seconds loading the thing isn’t going to hurt anyone.

This is, generally, not true for a web app with a caching service worker.