I looked into it a bit more and found that inactivity conditions for requester stops can be enabled if you enable the option to allow cargo at depot. I don't want to allow cargo at depots so I modified Cybersyn to allow wait conditions.
If anyone needs to do the same for whatever reason, here are the changes:
factorio-api.lua : 153
local unloading_inactivity_time = 200
local condition = {}
condition[#condition + 1] = {type = "inactivity", compare_type = "and", ticks = unloading_inactivity_time}
condition[#condition + 1] = {type = "empty", compare_type = "and"}
return {station = stop.backer_name, wait_conditions = condition}
central-planning.lua : 70
local r_enable_inactive = r_station.enable_inactive--[[@as boolean]]