Can linking verbs be used instead of BE in passive voice?

The second two examples have broken as an adjective. The get example has it as a past participle, and the be example is ambiguous.

The window was broken by the ball. [past participle]

The window was pretty broken. [adjective]

Try the same series with a verb that has a past participle which doesn't share a shape with an adjective.

The window was cleaned.

The window got cleaned.

*The window seemed cleaned.

*The window ended up cleaned.

The passive voice is made up of be or get and a past participle, whereas 'linking verbs' take a noun or adjective. Be can mark passive voice or serve as a 'linking verb' depending on context. Get can have a 'linking verb' interpretation, especially with comparatives.

The window got smaller.