Tested in 1.21 (not 1.21.1) on September 8, 2024:Whilst riding the strider, hold the fungus on a stick and right-click. This will cause durability loss and should grant the advancement (in survival at least).
asgerjon
Tested in 1.21 (not 1.21.1) on September 8, 2024:
Whilst riding the strider, hold the fungus on a stick and right-click. This will cause durability loss and should grant the advancement (in survival at least).