Conflict is often not bad chemistry but resources clustered in one corner, leaving a lower-ranking cat no way around or out.

Spread boxes, bowls, feeding points and resting spots across rooms, and make sure each resource has exits in two directions.

Vertical space adds layers: high spots for the confident cat, low and hiding spots for the cat that needs to avoid, reducing head-on encounters.

If chasing, box-blocking or marking persists, log the contexts and seek behaviour help. Punishment makes it worse.