Recovering data from a Mac that won’t start

If the internal drive is removable, then you can use an external USB enclosure to connect the drive to another Mac (2015 and earlier Macs). Which enclosure you need depends on the exact model of your Mac. Check with OWC for possible options.

If you have a USB-C Mac, then most of them have their SSDs soldered to the Logic Board so it will be impossible for you to recover the data without using an expensive professional data recovery service (Drive Savers, Ontrack), or see if you can find an independent repair shop that knows how to repair Apple Logic Boards (very hard to find a reputable shop for that type of repair and even if you do, the shop may be unable to repair the Logic Board because Apple prevents third party parts suppliers from selling parts to anyone but Apple). Even if you have a 2016-2017 MBPro 13" non-Touchbar model with removable SSD, I am unaware of any third party adapter or enclosure to use with the proprietary Apple SSD connector. If you have a 2018+ model with the T2 security chip, then you better hope the T2 security chip is undamaged since it controls access to the hardware encrypted SSD.

The only way to recover your data is from your backup. There are third party services that try to recover data from damaged drives but they are not always successful.