With the settings below a piglin brute still drops only around 10 cash, and it still shows a message ''You killed a PiglinBrute''
Don't think the configuration works on it..

piglin_brute:
enabled: true
message: ''
money:
amount: '20:50'
chance: 1.0
commands: []
head:
drophead: false
value: '0'
chance: 0.02
message: '&7De &3{killed} &7heeft een head gedropt!'

Seems it works correctly, but /mh reload doesn't take effect.

Also zombie_pigman should be changed to zombified_piglin

Please test 7.5.7

I will check the reload command. I never use this myself.