Think I'd check the battery connections first for both corrosion, & tightness, & then consider a battery; albeit I'd nab a cheap multimeter from Harbor freight or something & verify that the output is good, or not.
Motorcycle batteries don't last well if not run or kept on a trickle charger, & the factory ones tend to be dubious. I tend to replace them at the first sign of issues cuz I really don't want to deal with the hassle when I'm stuck in the middle of nowhere.
Folks will have their fav's for batteries, & they all have their merits.
I tend to be pretty conservative & stick with the YUASA AGM (Absorbed Glass Mat) batteries.
There are a few discussions on the merit of various types & brands, generic vs. YUASA or other brand name etc. so I'll leave that for them for now.