100 µF capacitors are no good for decoupling. Decoupling is about preventing spikes on the supply rails, so you need a low impedance for high frequency signals. 0.1 µF or 0.01 µF capacitors are what you want.
Put them as close as possible to the ICs that you want to decouple.
100 uF capacitors have a huge inductance.
https://www.farnell.com/datasheets/14936.pdf shows the impedance not reducing beyond 100 kHz. I suspect that the inductance may cause the impedance to increase at higher frequencies.
https://www.farnell.com/datasheets/618123.pdf shows that ceramic capcitors have impedances that decrease as the frequency increases, but as you increase the frequency further, the impedance increases. The point at which it reverses is at a higher frequency for smaller capacitors.
All of the ceramic capacitors have graphs that start at 1 MHz, while the graphs for the electrolytic stop at 100 kHz.
So you don't need the 100 µF capacitors. You might need one to keep the regulator stable. You need lots of 0.1 or 0.01 µF capacitors, as close to the ICs as possible.
50 mA seems a lot to take from the microprocessor output pins. That has little or nothing to do with the decoupling.