Ah I just confirmed this was errated, so that’s good one less thing to contribute.Create water doesn't create Supply.
Your suggestion about increasing the supply drain…again the fundamental problem for my group is, the ranger produces 3 supply every day, +2 when they succeed on a hunt check (and with their various bonuses they almost always succeed). So even if I just destroyed every supply container they have (meaning they literally carry 0 supply at all times), the ranger alone would still cover the party’s needs.
Probably the main solution is to remove the grub knack for the ranger in favor of something else. Without that constant refresh of supplies it provides (+ the errata on create water you indicated), that might do the job