Conceptual question on interpreting magnitude graphs
There are two notable things to say about the types of filter you have used: -


Passive filters don't need a power supply (a good thing) but they are much more difficult to design if you require steep rejection of out-of-band signals
You have cascaded two first order filters and their interaction will "muddy the water". This is due to loading effects of the 2nd RC on the first RC and the impedance of the 1st RC imposed on the 2nd RC.


If you want steep bandpass filters like this: -



Then it is likely you will need to use two 2nd order active circuits. I say this because the type of filter above has well-defined upper and lower 3dB breakpoints and a flat central area and this type of characteristic fits the bill for an active design.

However, if you want a characteristic like this: -



You can achieve it with an LCR circuit as shown. Note that there are two examples - one has a sharper peak than the other and this is due to the ratio of L to C.