I'm pretty new so take my opinion with more salt than usual.

I would optimize for the long-term. Maybe I'm reading too much into it, but it sounds like you're a little burned out of the stack you're using. I think it's important to work on things consistently, and you may make more progress using the stack that lets you work fastest, but you may get more burned out and then be less motivated to work on projects for a while afterwards. In the long-term, you may get less done.

If it were me, I'd try a minimal prototype in the new fancy language (and probably my best language for comparison). See how it feels and see if the advantages seem as large or as promising, and decide from there. From my perspective, this kills a few birds with one stone: you're less curious about the grass over there, you get to evaluate your new tech, and you may have a better idea about how to structure your implementation. That being said, it does cost time.

Hopefully this helps.