Minecraft 1.16.4
Forge 35.1.36
Quark r2.4-305

Trowel breaks after one use if you set the config option to 0(zero). Works fine in creative.

My config setting for trowel:

[tools.trowel]
#
#Amount of blocks placed is this value + 1. Default is 255 (4 stacks).
#Set to 0 to make the Trowel unbreakable
#Allowed values: [0,)
"Trowel Max Durability" = 0