"Normal income is subject to double taxation treaties, but from what I can tell, these wouldn't apply to corporations."
This simply isn't correct. Tax treaties and their impacts vary from country to country, but rarely are corporate payments excluded from consideration. In some cases there may be double-taxation without proper planning, but how that might occur and how you might be able to prevent it is a very specific question that would need a lot more details [among them: countries of income, type of income to the receiving company, actual method of payment, legal status in various countries, other forms of available income and taxes to offset, etc.].
"European countries typically do not tax income that was taxed under corporate taxes, so they don't experience this taxation."
This statement also isn't flatly true to my knowledge. What you may be seeing is in regards to withholding taxes between corporations, which is different than what it seems you are implying [that personal taxes aren't owed on corporate distributions ie dividends received]. See this link showing a 30% tax rate on dividends in Sweden when received personally [add this to a 20ish% corp tax and Sweden's overall tax on corporate income distributed personally is 50%, which is about the same as the regular tax on income in Sweden]: https://home.kpmg/xx/en/home/insights/2021/06/sweden-taxation-of-international-executives.html
Frankly it looks like you are in over your head here. STRONGLY recommend you hire a competent tax professional familiar with tax in both relevant countries as well as how their tax treaty operates.