You only need to go the employer for refund if they calculated incorrectly. In your case, the extra SS tax is not really an error, just a consequence of having multiple W-2's. If you've entered your W-2's correctly (i.e., entering all info in boxes 1-6, TurboTax will know that too much SS tax was paid and you will get a credit on your tax return.
It's called "excess social security and RRTA tax withheld" and should show on line 11 of schedule 3 and line 31 of 1040. https://www.irs.gov/taxtopics/tc608
There is really no need to involve the employer(s), unless they actually calculated the tax incorrectly.
