You mentioned 6-7h of sleep. I suspect you aren’t getting enough sleep and not stretching enough.

You said you went from sedentary to active. Do you have off peak weeks? Did you just start leg days? Is it muscle pain or joint pain? Do you stretch?

Your tendons and joints need time to build up. I suspect you did wide ranges, you’ve not been stretching, and you’ve really put a strain on the muscle ends. Stretch daily and move throw your motions.

I went through a similar relearning curve going from cycling -> cycling / yoga -> adding weights

If the stretching activity isn’t there, man the recovery sucks.

Good for you for doing it! You’ll figure it out!