Yep, it just works out of the box, that’s how nice the drivers are! You get updates to them as part of your Kubuntu updates, although there’s a PPA to install newer Mesa if you really want to. But for the most part, unless you need specific features of newer versions like for a new game release or a just released GPU, you can use the one that you already have just fine.
There’s no control panel because it all uses generic interfaces that also works for Intel and all other open-source drivers. For example, monitor configuration is configured from your DE’s display settings. You do need a third party GUI for overclocking.
If using Wayland, things like variable refresh rate is enabled by default and works out of the box. When HDR is ready, that will be turned on by default too most likely.