To make it short
Weapon types such as:
Billhook
Cane
Club
Hookhammer
Kama
Macuahuitl
Dire macuahuitl
Quarterstaff
Yari
Don't get a craftable option beyond a +3 one, and it's kind of odd because they have zero reason to not have such
None of those weapons are 3-crit range weapons, some even have just downright bad crit stats (club and kama)
So, my suggestion is to give those weapons a +4 option. Simple as that.