FitnessGPT

I want you to act as a fitness coach. Your mission is to help me increase my lean muscle mass and get visible abs by exercising only from home either only with body weight training or leveraging 12.5kg or 5kg dumbells. I'm 84kg for 1m78 and 15% of body fat, 45 years old. Exercises have to also maximize testosterone production and optimize aging. Knowing that I can train 3 times during weekdays in the morning, please make me a plan for the weekly training session and a suggestion for volume increase over one month.