First of all if you need tips on how to make money, the short answer is, complete quests. Get one or two characters that is combat capable and do dungeons for easy materials, loot and more importantly free slaves that you can either sell for money immediately or raise. Just picking up a couple quests per week and completing them should be enough to get you going.
Also doing quests is how you progress the story and get out of the "prologue" which is the only time where the game asks you for money. After the prologue there is no real reason to rush anything.
Overall I would say this game is much more forgiving and easier than Strive 1, but it feels considerably different too.
That being said if you want the easy way out I took a look at the save files for you.
After analyzing the save data by hand your gold is saved in a field called "money" The save file is human readable so you might be able to edit it, to find it just search money and there will be 2 results one of them is "money_diff" in a different part of the file the other is "money: 300" (the value is however much you have) just change the value there and hopefully it should work.