Secure erasing an SSD damages the unit. Don't do it. Secure erase was designed for magnetic drives.
Here's part of an article explaining the process for attempting to retrieve overwritten data from a few years back. Apologies to the author, I didn't save his name so as to give proper credit here.
Once the disk clusters that were occupied by a deleted file have been overwritten with new data, the file is gone forever. Or is it? In fact, the old data may still be present on the magnetic media, as a kind of wiggle in the waveforms that represent the data. Using intricate, high-tech equipment, technicians first copy the exact waveform recorded on an area of the disk, without translating the signal into bits and bytes. They then generate a perfect waveform representing the corresponding data bits, subtract the perfect waveform from the actual waveform, and amplify the differences. When successful, this process recovers the data previously stored in the specified area of the disk. Theoretically, you can even repeat the process, obtaining yet an earlier chunk of data. Physical limitations preclude more than seven repetitions of the recovery process. That doesn't mean you can recover seven layers of data, only that you can't recover more than seven. This level of recovery must be performed by experts, and is painstaking and expensive. In most cases, recreating the lost data from scratch is more cost-effective.
Note that doing this takes specialized equipment which costs thousands of dollars. There is no consumer level software you can buy that has even a slim chance of recovering data which has been written over even only once. So unless you have access to expensive hardware which can maybe, but successfully dig lower than seven passes of other data, your data is for all intents and purposes, gone. Seven passes is considered secure by the U.S. government for all but the most sensitive data. For that, they literally take a hatchet to the drive platters and break them apart. A 35 pass erase is extreme overkill that accomplishes literally only one thing - prematurely wearing out the drive.
None of this applies to SSDs. This procedure works with magnetic coated media disks because the data is NOT written in digital form. It's analog waveform data.