I'm not involved in data recovery, but I have a mini/mainframe background dating back to the early 1980s. Like you, I had a business maintaining such equipment. In those days PCBs cost US$10K - $20K apiece, so I made my living from on-site chip-level repair. I didn't have any competition (my competitors merely swapped boards), but today's PCBs cost only a few dollars. Even so, your electronics experience should give you a significant head-start over the typical players who include IT "technicians" and programmers. It's amazing how much ignorance there is in this area, even among those who have been in the business for decades.
Your big advantage, AISI, is that you already have substantial connections to the corporate world where data is valued much more highly. Perhaps you could consider specialising in RAID recoveries.
Actually, I'm thinking about blowing the dust off my toolkit and going doorknocking again.
US nuclear arsenal controlled by 1970s computers with 8in floppy disks:
https://www.theguardian.com/technology/ ... oppy-disks