Leaving any information on the hard drive that cannot be replaced from either a backup locally or from the cloud is irresponsible. the Genius Bar should have told you this prior to taking your device.
On two occasions in the past, I had devices sent in for repair where the hard drive was reformatted upon return. Both times were hardware related support requests.
Since a 2015 MBP might be hard to come by, I would say a refurbished 2020 M1 MBP would be the one they offer you with similar specs (the Intel models are cost more money in the refurb store over the M1 models). If they do offer a 14" 2021 model, surely feel lucky.
Did it have any battery? Did you see if you could locate it in find my device?
On two occasions in the past, I had devices sent in for repair where the hard drive was reformatted upon return. Both times were hardware related support requests.
Since a 2015 MBP might be hard to come by, I would say a refurbished 2020 M1 MBP would be the one they offer you with similar specs (the Intel models are cost more money in the refurb store over the M1 models). If they do offer a 14" 2021 model, surely feel lucky.
Did it have any battery? Did you see if you could locate it in find my device?