>>533850358
>is there any upcoming content that gives me a reason to invest heavily into my m.arisu?
Yes and that content is any boss where single-target blue damage is needed. Of which there are several.
But only if you really, really like her, to the point where you're willing to potentially subject yourself to the most mind-numbing RNG the game could throw at you.
If so then yes, she's still very capable of giving you scores that place you firmly into plat rank.

If you don't like her all that much, just use terror shiroko and save yourself the headache.