I have recently learned about infinitives. I know that infinitives act as nouns in the sentence rather than verbs, and that most infinitives are 'to + verb'.
Now bare infinitives have created a lot of confusion. Majority of the websites mention that bare infinitives act as main verbs after the auxiliary verb. My confusion is why we call them infinitives if they act as verbs? Or can bare infinitives work as a noun or noun phrase?
He does not sing well.
Does is an auxiliary verb in this sentence. So sing should be the main verb. But, infinitives don't act as verbs. Please help me clear up the idea of infinitives.