Update: My bike couldn't start again after I rode a short distance. When I push the starter, I can only hear the fuel pump and relay clicks but no cranking, similar to the symptoms when my stock battery died. I have narrowed it down to the battery because I could push start my bike running down a slope. I would advise everyone to avoid the green Tokiohama batteries widely available on Shopee, it's a big piece of crap. When I was doing my research for batteries to buy, quite a few riders on FB mentioned they swapped to this and the battery died within 5 ~ 6 months. In fact, my bike would intermittently not start if I didn't have rides longer than 15 minutes each time.

Did some research and narrowed it down to a few choices I found on Shopee:

Thai-X (RM150) - A lot of recommendations in FB groups.

Nippon G.R.P. (RM150) - MForce batteries that came with the RT3 scooters. Reviews seem a mix bag though.

Dynavolt (RM188) - Somewhat reputable Chinese battery.

Most likely getting the Thai-X.