perhaps you should read about https://en.wikipedia.org/wiki/Aphantasia ; people who can't visualize, but have no outward physical/mental issues. People who don't dream, etc.

Consciousness is likely not a single mode inside a single person. It likely is a distributed system; you can read about all kinds of psyciatric disorders, physical changes, etc.

You are using the "best" examples of what is it to think, rather than normative or even "depraved" thought processes.