Thank you for you advice.
"What I think is that most people would donate Bitcoin anyway so supporting many different cryptocurrencies wouldn't necessarily increase the likelihood of a donation that much. With this assumption just setting up BTC is enough and this is very easy to do."
But my reasoning is, that I know quite some people have different niche crypto lying around, hoping they will be worth something at some point, so instead of giving nothing, they might give at least them. And maybe they will be worth something, so I would happily take them all.
And I am only casual following crypto, but it seems, that ethereum is a serious player as well.
"Also, consider that when you use Coinbase you don't have access to your private keys. It means that should Coinbase decide that you are no longer entitled to access for whatever reason, you'll be left with no power over the funds. "
And of this I am aware of, but since I am a EU resident, not aware of any crime or money laundering, I suppose there is no reason to blacklist me. They have a reputation to be aware of (and I suppose I could make some noise, if I would be screwed over) - and I am more scared to be honestly, to make a mistake with the wallet generation. But otherwise I probably would be fine with a bitcoin wallet and etherium. I consider it.