Can't figure out what my wife does with her time

Hi Everyone, My wife and I have been married for 15 years. During that time, it has been no secret that I'm a much higher energy person than her. Both of us are generally healthy individuals. She has gone to the doctor to determine whether her low energy is the result of a medical issue. They did put her on a thyroid med, but very low dose because it was borderline normal. Her lack of energy has extended into many areas of our lives. The two main ones are fitness and housework.

Fitness is an area her and I have clashed on a lot, and it has caused more than one argument. I worry about her health. Her BMI puts her in the obese category. If she didn't care, fine, but she regularly makes comments about how she needs to lose weight. Note: I'm very into fitness. I play tennis 2-4x/week and lift weights 4x/week. Not sure it matters, I just want to make it clear that I'm not calling the kettle black.

In terms of housework/cooking, we have cleaning people come every other week. There is just some touch up to do in the middle. I do most of it. I also do at 90%+ of the laundry/folding and 100% of the yardwork. My wife does most of the cooking, and historically that was the thing she went over the top with, but recently she started ordering meal kits on like for 4x/week, but another night or two we order/go out. I cook occasionally, maybe once a week.

When I have tried to broach this subject in the past, she has insisted that I have no idea how much stuff she needs to do that I don't appreciate. She mentions things like shopping (grocery shops online, almost never goes to the store), anything that needs to be done for our 11 year old son (only child, and I do 100% of his sports related stuff and some of his school related stuff), bills, etc.

PS: She works part time, I work full time. I asked her about going back to work full time recently and holy hell, did I hear about that one.

I'm looking for advice on how to approach this. It's honestly driving me nuts, an having a real impact on our marriage.

tl;dr: I do WAY MORE around the house than my wife and work full time, she works part time. She insists she's super busy, but I just don't see it. Help!

Thanks!