Comma in coordinating conjunction that includes an if-clause

On the basis of this Q&A, I understand that my example sentence is a coordinating conjunction; however, I can't seem to figure out the relationship between the first clause, and the if-clause. Should there be a comma before the or and why?

Please let me know your thoughts *(,)*or if you experience any trouble opening the attachment.

There should not be a comma.

A comma is used if the coordinating conjunction (e.g. or) separates two independent clauses. Example:

Please let me know your thoughts, or reach out if you experience any trouble opening the attachment.

There you have two independent clauses in the imperative form—let me know . . . and reach out . . .

Your coordinating conjunction does not do that; instead it separates an independent clause from a dependent (if) clause. Yours can be understood like this:

Please let me know:
• your thoughts
or
• if you experience any trouble opening the attachment.