I would suggest trying to get to grips with the mod's economy first, but if you want, you could make a simple edit a file to increase your capital's credit income, but be aware that it requires a new game.

- Go to Steam - steamapps - workshop - content - 32470 - 1976399102 - Data - XML
- Find 'planets' in that folder (As always with any file editing, make a backup of that file first, and put it somewhere safe - if something goes awry, just copy-paste-replace the original back in)
- Open that with notepad++
- Ctrl+F and search for the name of your faction's capital planet (Coruscant for Republic)
- It will look like this: <Planet Name="Coruscant">
- Look for <Planet_Credit_Value> underneath it
- Change the number next to that, and save

I strongly recommend you don't increase it by much, a few hundred at most probably, because your capital has significant planetary income boosting buildings on it and, instead of giving yourself a little boost, you can RAPIDLY trivialise the game if you add too much, but it's your single player experience, so you do you :)

Edit: PS - If you play as another faction afterwards, be aware that if you keep this modded file in as was, that (Now enemy) planet you changed still has the boosted income.