There's a lot to unwrap in your questions, so I won't answer them fully. But I work in a job/industry that I consider to be meaningful and have done so for about 36 years. I work in the environmental industry, specifically waste management and air pollution control.

When I graduated with a ChemE degree, I decided that I wanted to do something positive for the environment. I didn't know how to start, so I just applied to companies with "environmental" in the name. That's how I got into the air pollution control field. Note: back then the internet was called "books", so I spent a lot of time in the library looking up companies.

Most companies have internal IT departments that write and manage line-of-business software. Find companies that do something _you_ find meaningful and try to get into their IT departments. Once you're in, recognize that no job is going to be seventh heaven every day. Make the best of whatever you're doing. It's a lot easier to do that if you're in tune with the company's mission.

My way is not the only way, of course, but that's what works for me. Good luck.