I understand why it takes 15 pages of comments to cover a relatively simple design with
MrDEB . He does not ask the right questions and makes bad assumptions, but he tries hard!.
You need a gate supply voltage at least 2x and preferable 2.5V times the max Vgs(th) threshold voltage for the IRF xx series FETS (eg IRF520) .
These are a poor choice for 5V expecting high current. OK for maybe 0.5A but NOT much more unless well heatsunk.
FETS have a very high impedance like 10 to 16 kohm at the threshold called Vgs(th) or Vt.
But the IRFxxx series are all old school Vgs(th)= 2 to 4V. If you are lucky to get parts that are Vt=2V , it works , 3V maybe and if they 4V never works well at Vg=5V. Thats a problem with FETS is the threshold has a 50% tolerance. So you need "LOGIC LEVEL" FETs which work well at 3.3 or 5V because the Vt threshold is about 1/3rd of the gate voltage used or less. So if you use no heat sink, consider 1/4Watt and I^2*Rdss = P even if it is a big TO220 to avoid hot parts.
So if you had 5m or 5A to keep the FET cool, RdsOn=Pmax/I^2= 0.25/25 = 10 milliohms with a Vgs(th) max < 2V (not minimum).. You may find these parts are rated for > 10x what you are using because I assume you might use no heatsink, using the thermal resistance Rja * P = Temp rise ['C]
This is important to understand when using enhancement FETs.
Lesson to learn: Not all resources on the web are reliable.