You could try to use plymouth.
Be aware though, that Plymouth works in a rather... strange way in Solus. At least, for me.
While all standard Plymouth themes are installed along with the package, spinner is the only actually usable theme. Even though you may choose and setup any other of standard themes, only spinner will be used on startup-shutdown despite of a chosen theme.
I have a bunch of my own animated Plymouth themes, which I made by hand a few years ago. Paradoxically, all of them work perfectly in Solus. As they're infinitely more beautiful 🙂 than default themes, I never investigated why the latter do not work as they should.
