Just made a custom cheat for current latest steam version that sets all resources to max storage size. Do note that it only triggers to max when a resource increases/decreases. Recommend turning it off as soon as you got the resources you needed.
Not really well tested, but worked for me.

Author: marking

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• Frostpunk: Trainer +13 v05.09.2019 {MrAntiFun / WeMod} [2019-Sep-05]