Like all correlative conjunctions, “not only … but also” does not typically require a comma (e.g., “The weather forecast calls for not only rain but also hail”).
The one exception to this is when it is used to join two independent clauses, which each have a subject and a verb (e.g., “Ava not only speaks Spanish, but she also is learning French”). This sentence could also be rephrased to not require a comma (e.g., “Ava not only speaks Spanish but also is learning French”).
A QuillBot grammar check can help ensure you’re using correlative conjunctions correctly.