How to recover data from Mac after a repair?

Exactly what work was done?

If they replaced the logic board, you don't have the original drive any more, so there is nothing recoverable. The storage, a solid-state drive, is a non-removable part of the logic board in that model that cannot be separately replaced or moved to a new board.

Call the place you asked for repair and ask them why they didn't ask if you had a backup, or why they erased your system without telling you they would? You should never expect to be able to recover information after an erase. You can ask them if they have the ability to recover information. The one place that does have the ability to do it with some success rate, is http://www.drivesavers.com/ but they are very expensive. Given this happened though as a surprise, you should really call the place that did the repair first and ask why the gap in communication.

Yes, but they need to be communicating with you before they erase anything.

Clean install to some means erase the computer and install a new.

If that's not what they did, the information may still be there. You can try to use

https://www.devontechnologies.com/apps/freeware

EasyFind to see if anywhere on the hard drives the files still exist. If they don't, then you need a data recovery to be done.

After an initial erase the first thing lost are pointers to files, and not the actual files themselves. Depending on how full the hard drive is, a good recovery software may be able to recover that information. If though a zero erase was done, or all the pointers were overwritten, there is no chance of recovery. How this "clean install" was done makes a difference. It used to be Clean Install meant something totally different:

kmosx: Installation options and their mea… - Apple Community

This is why it is vital that any place that does repair discuss with you any erase procedure before it is done, to ensure you do have a backup in place, or understand the risks of what the repair will do.

It does not matter what they repaired. The fact is you lost your data by not having a backup. Data is your responsibility not the repair shop's responsibility. The first bullet in this Apple article indicates that you must make a backup prior to servicing your computer:

Get your Mac ready for service - Apple Support

xxxtentacles wrote:

this is not helpful information for my case, definitely good information for the future however the apple store representative could have done a much better job at explaining that data loss would occur.

Data loss could occur at any time. This is why it is basic procedure for all computer users to maintain a current backup at all times. The article provides an additional data backup warning, but users should have a backup even when a computer is not scheduled for repair. Sorry about your loss.

The IO board of all 2019 MacBooks includes the storage of the Mac, and can't be separated from it. Many they have equipment to read the data straight off the board, but some I don't know if that's true of every one.

It really is something you need to discuss with where did the repair and explain to them you needed them to let you know the consequences of doing the repair before going through with it.

I am really sorry you lost your files, including treasured photos.

Your loss is tragic, but is caused by your own negligence. You have deviated from standard practice in a significant way.

The papers authorizing the repairs states you agree you ALREADY have all the backups you need, and allows them to proceed without asking additional permissions. They do not need additional consultation with you, and they have that in writing. Did you read what you agreed to and signed?

Apple provides the excellent free Utility, Time Machine. It is already built into MacOS, and all you need do is connect an external a drive and tell it to GO.