1N4148 are low power signal diodes & would happily pop to "protect" the fuse....
The symbol used on the circuit diagram suggests a schottky diode ie for low fwd drop in the reverse situation.
You'd want the diode to survive an accidental reverse with associated high current pulse while the fuse blew so it would need to be rated probably 3A for 2A fuse
Something like a 1N5820 might do it.
There's a way to use mosfets as reverse protection, google "mosfet reverse polarity protection"
eg https://hackaday.com/2011/12/06/reverse-voltage-protection-with-a-p-fet/
With this method, the fuse doesn't blow, no current flows so nothing happens.
It might take a low gate voltage type to work best & batteries with low voltage might not work too well or need a kickstart, etc
The symbol used on the circuit diagram suggests a schottky diode ie for low fwd drop in the reverse situation.
You'd want the diode to survive an accidental reverse with associated high current pulse while the fuse blew so it would need to be rated probably 3A for 2A fuse
Something like a 1N5820 might do it.
There's a way to use mosfets as reverse protection, google "mosfet reverse polarity protection"
eg https://hackaday.com/2011/12/06/reverse-voltage-protection-with-a-p-fet/
With this method, the fuse doesn't blow, no current flows so nothing happens.
It might take a low gate voltage type to work best & batteries with low voltage might not work too well or need a kickstart, etc