When while is used as an adverbial clause to guide time, if the action (past occurrence) of the clause itself is continuous, you can use the simple past tense directly, without changing it into ing form or becoming a progressive verb.

While also means "although", which leads to adverbial clauses and is placed at the beginning of the sentence. At this point, the while clause should not be a continuous verb.

While also means "harmony". It is placed at the beginning of the second half of the sentence to guide the complex sentence, and it is not required to be a continuous verb.