Metaformin could. But so could lazy keto. Could also be that you need to do intermittent fasting to drop your insulin lower as it could be insulin resistance or just insulin spiking if you are eating more often throughout the day.

Higher insulin and insulin resistance are major issues with losing weight. Have you tried intermittent fasting? That can give your body time to lower your insulin. I would also recommend doing clean keto. Sloppy keto and eating frequently won't help lower your insulin especially if you have insulin resistance. Would also highly suggest reading The Obesity Code by Dr. Jason Fung. It's extremely enlightening and will help you understand all about insulin and how this can be impacting your weight loss so you can look at what you could do to take more control of it.