grammar - Is putting a comma before two non-coordinating conjunctions still correct?

Can I put a comma before 'or' in the following sentence:

Airline work can earn double the salary of factory work, or at least equal

Background:

The rule says you need a comma before a coordinating conjunction: and, but or etc

The rule does not say anything about putting a comma between two non-coordinating conjunctions

'At least equal' is not an independent clause so it's not a coordinating conjunction

Therefore, if I put a comma before 'or' is that incorrect?