I came from a mech eng background, got a master's in computational and applied math (no formal computer science), and have since had two different software dev

I came from a mech eng background, got a master's in computational and applied math (no formal computer science), and have since had two different software dev jobs. There are lots of places that don't require a formal CS education. If you have programming experience, have done projects, and have demonstrated an ability to learn and solve problems, that goes a long way. There are also places that hire mechanical engineers and the roles involve a lot of software development; maybe not the exact role you're looking for, but it can be a pivot.