Can we use "only" to modify/emphasize auxiliary verbs?

1. I only can't sell this furniture and this carpet because they are too big.

2. I only can say, “yes,” I can never say, “no.

3. Only don't lock your door. (Here, "only" looks like modifying "don't)

4. I only don't know how to do that.

5. I only could play the music for other kids and watch them dance

6. “No, no—I only should have had more time. I want another go.”

7. I only must ask you to excuse the disorder in which you find us.

I found all the examples in Google books.

I think in each case "only" seems to emphasize/modify "can, don't, could, should, must", but I'm curious whether it is correct to use "only" to emphasize/modify them like in the examples.

I'm not sure whether it is possible to use "only" to modify them.