Onward from Luxembourg?

I’m planning a trip to Luxembourg in October. I was hoping to get some suggestions on where to go next. Plans are fairly open at this point, happy with any suggestions!

We will be arriving from Paris so I plan to avoid doubling back there. We also visited Belgium and the Netherlands last year so I was not looking to head that direction.

Direct flights seem to be fairly limited in October and November. Slovenia, Malta and Dublin are available, which seem like nice options.

I have also considered Strausbourg/Colmar or Frankfurt as the next stop if we go by train.

Looking to eventually make our way down towards Prague/Slovenia/Croatia/Greece.

Any particular places people tend to go from Luxembourg? Interested in hearing what locals do for shorter trips or what other travellers have done that did or did not work well.

Any suggestions are much appreciated!