None of this is an actual problem. You're completely normal. You need to worry about fixing your lower outer pec as much I need to worry about how I'll introduce myself when I meet Arnold Schwarzenegger.
That's fine. Nobody needs to workout daily.
This is a problem. Stop taking weeks off.
So... high rep sets.
Get on a better plan. Either try to save up and buy a few more weights to use or follow a better training routine. For example, doing deadlifts and squats for 30 reps with 15kg is accomplishing basically nothing.
To build more muscle and strength, use a weight that, instead of being able to do 30+ reps, it's challenging to do more than 12-15. That might mean using different exercises like one-arm or one-leg variations (one-arm row, one-leg deadlift or lunge, one arm press, etc.)
What's your specific goal?