So I can loop through all my data in the Next..
self.datas is an array and you can loop over it.
How do I plot the portfolio performance? instead of backtrader printing 1000 different charts...
Depends on what you have defined as performance for your portfolio. There is for example a TimeReturn observer which is intended to plot exactly what the name implies.
If you want to plot other performance indicator, you will need to define it as an indicator or observer
The default is to plot the evolution of the cash and the actual portfolio value which should give a quick indication as to where the system is
And only a single chart will be printed per strategy.
Is there an integrated solution to do this in Backtrader?
There are several samples, blog and documentation pages. See for example:
Here the performance is defined as the comparison against another asset.