In Latin, like in many languages, the usual present tense can be progressive.
For example, "I am acting" would be simply ago.
If you want to make a distinction between "I act" and "I am acting", you need to use other words to convey the nature of the action.
Usually the context alone is enough, but you can add words like "suddenly" or "continuously".
In my opinion, the answer to your question is no.
Something like agens sum means "while acting, I am". In Latin, participles function a bit like subordinate micro-clauses.
incensus irato, pura mente, ovem agens, sum
burning with anger, with a pure mind, leading a sheep, I exist / am.
To be and a participle does not create a predicate as in ...