is this a compound sentence
Secondly, regular use of social media can result in low self-esteem, comparison anxiety, and feelings of not being good enough.
Yes, the given sentence is a compound sentence. It consists of two independent clauses joined together with the coordinating conjunction "and." The two independent clauses are:
"Regular use of social media can result in low self-esteem, comparison anxiety, and feelings of not being good enough."
"Secondly," (independent marker) initiates the second independent clause.