I take very often the train to go to Brussels or Antwerp, very cheap because I am an old man: 7.20 €. Cheaper than taking my car!
They have an app (the railways I mean) and in less than 2 minutes, I think even less than one minute, I have paid and my ticket is on my phone. I would guess Deutsche Bahn has also an app.
But indeed there are uncertainties.
And specially for
@emax , another country I have been is Syria on my own, by train from my city through Germany (partly with the ICE, indeed very good!), and through Austria, Hungary, Romania, Bulgaria and to the middle of Turkey. The rest of the trip was with small busses, taxis, etc. That was in 2010, the year before the war, I was lucky, saw things that don't exist anymore. Allepo (Halep) was a magical city, so beautiful. I finished in Jordan and Israel. I came back by plane.
Syria was a splendid country with very nice people! But I felt several times that state agents were watching me. Some "friendly" people always asked me where I was going
I didn't do it by car, because it would have taken me double the time, and I was still working full time.
Now, I would do it by car (Grenadier of course), but I guess it is still not everywhere safe.