[1.16]Use capability in client only mod

I'm trying to create a mod (client only) that shows the health of entities in sight. Like the player's overlay health, I want to animate things like highlights, so I need to keep fields lastSystemTime and etc. To implement this, I have two ways:

1. Create a HealthRenderer class that holds fields lastSystemTime and etc, create a map with the corresponding entity, and retrieve the HealthRenderer class and draw when the entity is in view.

2. Attach Health Renderer class to each entity by capability

If the capacity isn't available in the client-only mod, I'll use 1, but I'll have to keep fields about all the entities that have been in sight, and check the map every time it's rendered. Can capability be available in client-only mods? Or is there a better alternative to 1 and 2?