Cannot apply themes downloaded from Software store

Not sure what I’m missing here, but I have the Tweaks app installed, I have Gnome User Themes installed.

I go to the app store, I download a theme, for instance Arc-Dark-Solid which I would assume would automatically add itself to the Tweaks menu for theme selection after installation (and reboot), but it doesn’t get added.

What am I missing?

Thanks

Looks like that one might be out of date.
Check out gnome-look.org for up to date themes.

Fair enough, but are there any theme’s that will “just work” by downloading them from the App store? For instance, “Orchis” is a modern / up to date theme with the same issue when installing via Flatpak.

Theming Gnome can be a bit tricky. When done right it looks great but it takes a few steps, and sometimes a new Gnome version can break your themes.
As for a simple just work, there was Gradience but it’s no longer maintained.
I ended up making my own theme.

If you want to know more I can walk you through it.

Here is my current desktop, shows what you can do.