There was a pprune user Tricia Takanawa who had similar thoughts a few years ago when i was joining. We exchanged a few PMs but I'm
not sure what happened in the end, I lost the password to that account. But you might have luck looking them up to see how it went.
From my side, BA isn't the be all and end all, if you aren't fulfilled here now it's unlikely you will be in the future, and is that possibly more a function of airline flying than the particular airline? In that case I doubt moving to VS/J2/EZ/RYR etc would solve that for you. But aviation is big and there are many different roles around the world that have different challenges, so if you are in the position to go seek these out give it a go!
I'm staying at ba myself because i still enjoy it, and I am supporting a young family so i value the regular paycheck and plenty of time off at home.
If I had got into BA at a young age, I think I'd be itching for an adventure. However I did my adventuring earlier in my career so a nice easy stable airline job suits me down to the ground.