Hi,
I have had a quick look at this.
If I start with a very simple model for the photodiode, a current source in parallel with the junction capacitance.
I get the following model:

I am showing two test circuits, the OP amplifier and an ideal amplifier.
The result is:

The performance is dominated by the amplifier, not the PD.
I would start by reducing the value of the emitter resistor on the first transistor.
I have attached my LTspice model.
I did not model the BFP420 transistors, because they have two emitter connections, they are including package parasitic inductance etc.
Regards,
Jay_Diddy_B
TIA Model.asc (3.69 kB - downloaded 308 times.)