If you have an extra tank, here's a trick I did that I learned from one of Tom's stories.. not sure if it was this one and don't feel like verifying. I took my BBA infested anubias and java fern windelov ( you definitely can't scrub those leaves! ) and just unceremoniously dumped it into a low tech, low light, no co2, barely dosed tank. I don't even recall planting it. Neither of them cares too much if they're not rooted. Like you, I was ready to throw it out, but figured what do I have to lose. Ignored it for months (Tom's story was that he left his plant in an ignored tank in the garage) and just like that, when I cared to check up on it, the BBA faded away. Prior to this, in my main tank, I had peroxided it repeatedly, watched in glee as the BBA turned red, and cursed in frustration as I broke out the peroxide again as it cycled through to a new generation.
Does this help your main tank? I dunno. I can speculate about it and I probably have before, but I'm sure you're aware of the generalities and seem a little burnt out so you need a break. If this works, maybe it'll give you a small taste of success, and give you the confidence to fight it again. If nothing else, it'll give you an excuse not to throw your plant out or an excuse to start another tank!
Be warned though, don't just throw it in a bucket of water. These things sort of melt if there's no water movement. In a different situation, I unintentionally melted a ton of java fern that way.