It’s really hard to suggest anything with regards to driving line or braking/acceleration points via the internet.
The biggest thing would be to minimize your coasting time. As soon as you’re off the brakes you should be rolling back into the throttle. If you’re coasting, you aren’t maximizing how late you can brake or how early you can get back on the throttle. Minimal coasting will help a lot.
Try driving harder into the corner and braking harder so you don’t coast and you can get back into the throttle quicker. Or try slowing the kart down a little earlier and powering through the corner.