Never heard of any NTA or of business expenses being converted into money to myself when it's not on my account. Looking up what an NTA is in relation to taxes, they're a nonprofit themselves and don't appear to have authority of any kind besides PR
https://en.m.wikipedia.org/wiki/National_Tax_AssociationRegardless, if this were a concern in Germany, I'm sure our boss/director would have mentioned it on that call as a simple reason rather than finding excuses and saying we could pick a different nonprofit who needs it more to donate to
Companies donate all the time... this argument about it being considered income makes no sense, and if it did, just donate {income tax rate}% less if the company can't afford more and no problem either