Easiest solution would be to work on your grip, you could use those hand grip tools that you squeeze. I personally don’t like lifting in gloves, I feel like the bar slips more, especially when my hands get sweaty, you could try to use chalk and see if there’s a difference. In the past I also had trouble gripping, but it was due to a tightness in my shoulder, a nerve was getting pinched, so I couldn’t hold a tight grip too long. If all else fails I’d suggest going to a physiotherapist to see if there aren’t any issues in your arm. In any case good luck, keep it up!

As a front-end developer with 10 years of experience, I’d suggest going with JavaScript. It’s one language for both stacks, you can learn the core front and back end ideologies, and if you decide to go with a different language for back-end, it shouldn’t take too much time to learn afterwards. From my experience it would be easier both to learn and potentially to get a job in the field.