It didn't come across as combative at all, no worries. I find it pretty convincing to be honest. If anything I think the biggest hold-up is that I can get jobs as a senior front-end engineer but if I looked for Ruby jobs I'd kind of be taking 2 steps back down in terms of what I can contribute.

Frankly I'm not a fast learner, unfortunately. Although it's possible that I've convinced myself of that because I hate the Java ecosystem so much that my brain just doesn't want to absorb information about gradle and intellij configuration and java dependency management and so on.