May I ask why you installed the icon theme and the GTK theme in the way you described?
I am not an expert, just an interested Ubuntu Budgie user who also likes the look of Solus Budgie. Just take a look at my current desktop.
With Budgie Welcome, the Ubuntu Budgie developers have given us a handy app that makes it easy to customise the look of the desktop according to personal preferences. If you want your Ubuntu Budgie to look like the default Solus Budgie, all you have to do is start Budgie Welcome, go to Themes & Layouts, install the Plata theme and then apply both the Plata makeover and the Traditional Budgie layout, as described here. If you prefer a darker theme, you can easily adjust this accordingly in the Budgie desktop settings by choosing the darker variants of the icon theme and the GTK theme.
As you can see, Ubuntu Budgie users don’t have to search the internet to find the appropriate icons and themes for the desktop customisations mentioned above. Hence my question.