I hear this a lot, but it doesn't seem true anymore. Every country I go to in Europe, tipping culture is creeping in and more expected in small amounts.

In Germany it's pretty common to tip a bit, even if not nearly as much as in the US. I wouldn't know what to tip for a 300€ order though because... What the fuck, did they order cocaine?

In many cases, yes. But when it comes to delivery services like this that has a history of underpaying and bad working conditions it just makes sense to tip IMO, and absolutely do it in hand and not via the app or whatever. I very rarely order food, and when I do I always try to stay clear of these kinds of delivery services. But it's often hard to so, and when there's no other option I always choose something that has a deal and then give the difference to what it would have been directly to the delivery person (not sure what the right word here is).
About a month ago I was at my moms place with my half brother and the local delivery app, foodora, had a 40% deal for any order from our favourite pizzeria so that was an obvious choice, when I gave the 40% of the total to the delivery person they almost started crying and that just felt so damn good. It absolutely sucks that this situation even happened, they should be paid more and have way better working conditions etc. but we all do what little we can with the reality we're in. I made some actual difference for someone and I'll take that.