The libraries & dependencies would be a problem. I think it is probably the reason that projects like Lightweight Cross-Platform (Windows/Linux/MacOS) Splash Screen exist. (That one is a BSD 2-Clause License. But other projects may exist.) However it is unclear how such a Splash Screen should be integrated into the launch sequence.
In the old DOS days, instead of a launching the .exe application, we’d link the application icon to a .bat batch file. The batch would spawn a lightweight Splash Screen thread, then launch a loader program. Finally, it would kill the Splash thread only after the loader reported a successful initialization.
I’ve gotten accustomed to latency in loading behavior and can ignore it. This kind of Splash screen suggestion is just about the first impressions of new users. I don’t know if it is worth the vetting process.
However, I do have hopes that someday I could distribute our Family genealogy WITH Gramps… WITHOUT hearing back that they gave up in frustration.