Camera Selection

Hi all and thanks for all the support on here so far.
I am looking at new cameras for the home cctv. and was hoping someone had some positive news with which are the best cost effective cameras for internal and external.

I was about to buy a load of bits from Aliexpress and thought i would ask if anyone has any solid experience.

I have one more complex question.

I have a swann DRV system currently and was wondering is there a way to make my dumb cctv smart.
Whilst I can view the cameras remotely I cant link motion detection to them etc.

So I was hoping that maybe I could just buy a new DVR box and plug the cameras in to that and that DVR box be less dumb. The camera all have cables run to them so I could utilise these cables and in time upgrade the cameras them selves

I hope that makes some sense