I don't know what people generally recommend now, but for a long time the best practices with organizing React components had them connected to the store midway down the tree or higher, which definitely would have contributed to the UI slowness since it would rerender everything below that on each update. Push the store access down as far into the leaves as possible and you won't get anything noticeable, even though it is still doing more work than just accessing the DOM state as needed.

Also, focus management isn't really a thing in React, the vdom diffing means DOM nodes are updated instead of replaced so focus isn't lost or changed unexpectedly. There used to be a demo on the React homepage showing this, since the idea was very new to most people at the time - everything popular before it was just rendering template fragments to replace nodes and did have this problem.