No — there is no app store, theme installer or watchface gallery for the Artemis Watch 2.0, and nothing to download onto it in that sense. What you add to the watch, you build.
How adding things actually works. You code the watch through CircuitBlocks at code.circuitmess.com — your own watch faces, animations and simple apps. Two expectations to set straight:
Your program replaces the stock software while it runs — it does not appear as an extra app alongside the built-in ones.
Programs run from memory and clear when the watch resets. Your sketch stays saved in your CircuitBlocks account, and you run it again after a power cycle; the Restore firmware button brings back the standard watch whenever you want it. The detail is in Why doesn’t the program I wrote in CircuitBlocks stay on the device after a reset?.
Community projects exist — as code. Other owners share what they have built on the community forum and in our open-source repositories on GitHub, and you can study or adapt their work in your own CircuitBlocks sketches. See Is there a community forum where I can show off my projects? for where the community lives and What is "Open-Source" and why does it matter for my kit? for what being open source lets you do.
If you are new to it, Coding your Artemis Watch 2.0: where to start is the gentler on-ramp.