A friend of mine is a big fan of him https://www.amazon.com/Kettlebell-Simple-Sinister-Revised-Up...
“Simple Sinister” is a program with kettle bell swings and Turkish get ups - it is a good basic program for general core strength when you have limited time. Look at what Tim Ferriss has to say about the swings.
Add https://stronglifts.com/5x5/ too.
Add some cardio you enjoy, preferably daily and at least 20min, but not too much you are exhausted. You should still feel quite fresh afterwards.
Eat more vegetables, try to hit 5 portions a day minimum. Dr Weils “Optimum nutrition” book is a great book on the basics.
An IF protocol with a daily energizer routine worked wonders for me.
Some great reads: https://www.amazon.com/Kettlebell-Simple-Sinister-Revised-Up... https://www.amazon.com/Strength-Rules-Stronger-Almost-Anyone...