[gumby]

Do you enjoy what you do? js front ends aren't going away any time soon (inevitably they will someday, of course).

Anyway, if you like what you're doing and are just wondering if it's safe, why not expand your skills rather than jump to a separate pond. To use metaphor: "increase size of your circle" or "learn something in an overlapping circle".

Also, I suggest expanding first in the area of fundamentals. You mentioned SQL: it has outlasted many fashionable programming languages and is likely to do so for quite a while. Or improve your on algorithms and DS skills a bit. This is because the "next language" is statistically going to last a short time, while the deeper skills will make you better with whatever the fashion of the day happens to be at some time in the future.