How to do this sort of depends on your configuration, but the short answer is yes.
Generally, if a port supports eARC, it also supports HDMI-CEC and can pass volume and other controls across from another device, but of course not all TVs are designed for this. However, I can actually use the remote for my LG CX to fully control my Apple TV 4K — the d-pad on the LG remote can be used to navigate all of the Apple TV menus, and of course by extension the volume control works just fine too. This all happens over the HDMI connection between the TV and the Apple TV 4K. So, volume controls also work when viewing other sources, whether that's native webOS TV apps or an HDMI input from a DVD player or PS4.
Note that you might need to switch HDMI-CEC on in order to enable this. Different brands call it by different names (i.e. Anynet on Samsung, Simplink on LG, Bravia Sync on Sony), and not all support the full range of HDMI-CEC controls, but it's still the same protocol either way.
However, even if you don't have full HDMI-CEC support on your TV that allows for this kind of control, you can still pair any IR remote with your Apple TV 4K and use that to control the volume and other functions. This is done under the Remotes and Devices section in the Apple TV's Settings app. Unlike the Siri Remote, you'll need line of sight to the Apple TV as it runs over IR, but it otherwise works quite well, and you can even use it in tandem with the Siri Remote as well.