I decided that this plugin was probably easily implemented with a datapack, so I put that together tonight.
This is an early version, so all functionality is subject to change!
Configuration can be changed by modifying the values in the dev_satyrn.archers_of_decay.config
scoreboard. I'll see what I can do to make the config easier later.
A new plugin version for 1.21+ is in the works, but I'm getting slightly bogged down in details with my helper library, so please pardon the dust.