Manufacturing quality assurance. I don't have a ton of mech engineering in my area, so I broadened my search by just using "engineer". I had to sift through a lot of software/dev/etc engineering listings. I noticed there was a consistent stream of quality engineer, quality system type roles. Applied, and now it's my career trajectory.

It's a bit niche, the "real" engineers want nothing to do with it, and I get to dabble at various levels into all the products and processes. It comes with a good amount of documentation, auditing, pondering the true intent of accreditation requirements, and other mundane tasks, which is why so many people hate it. But maintaining the quality system maintains the business, so I have a job.

It's not ISO 9001, but it's similar. It has a ton added that's specific to the industry, so it's tangibly useful. Personally, I think ISO:9001 is a pyramid scheme. Under 9k1, you have to vet your vendors... Unless they're also 9k1 certified! Regardless, I'm surrounded by 9k1, so I have some local mobility as well as national mobility for the specific industry.