basically i think it's perfectly normal for ecs setups to have many of these "1:1" things, ie. one component fairly tightly bound to one system (which might depend on some other components too). you might even want to colocate the component and system in the same file for convenience

but those systems can depend on other components (either other "behaviours" you defined or built-ins like physics, transform, rendering etc, of which you'll usually need at least a few to do videogame type stuff)

iirc you never really used unity but i think the way it works (before it introduced its more recent, opt-in "proper" ecs) might be a useful point of reference? you have entities and component-systems fused together (as "behaviours"). ie. there's a 1:1 relationship between components and systems

i don't think anything is cheating!! it's just about flexibility and ease of breaking things out down the line, right? imo a good heuristic (not just for players, for lots of things) is like "chunky until proven otherwise"

exciting! looking forward to hearing how it goes