I just tested the compatibility with horizon theme. all in all it’s basically working, but the only issue is that the plugin outlet currently used by the category headers theme component is inside list-controls container on Horizon theme. Hence the whole category header stays sticky.
Suggested solution is to change the plugin outlet or add an option to choose a different plugin outlet outside list-controls container, e.g. discovery-list-controls-above outlet.
I can spin up a PR if you want @NateDhaliwal