It looks to me like the circuit has two separate capacitor limited transformerless supplies.
If so, I would repeat that all of it should be regarded as potentially at lethal voltages.
I think that the larger capacitor controls the current to the LEDs. If so you could try putting a capacitor in series with the existing capacitors.
The capacitor should be a bit smaller than the existing one. It must be non-polarised, and rated to 400 V or more. It is a good idea to put a 1 MΩ in parallel with the capacitor, just the same as has been done on the existing one. The resistor will discharge the capacitor within a few seconds when the circuit it turned off. Without it, the capacitors could stay charged for ages.