Tips for what to do in Kuala Lumpur?

Hi! I'm in Borneo right now, headed to Kuala Lumpur tomorrow. I have 3 days there, and I already spent 2 days there earlier. So I've already done Batu Caves and the fireflies. I'm wondering what to do for those three days? The only think I'm solid on is I want to do Malacca one day. I was thinking of also doing a city tour one day? But stuck on what to do the last day. I wanted to go to Taman Nagara but I'm a solo traveler and couldn't figure out a way to get there and back for less than 350 USD. Anyone have any ideas for how to kill a day in KL? Are there good museums or historical sites to see? I looked at cameron highlands but I've already been to colmar tropicale and I think they're pretty similar.

Appreciate any help!