Brussels-Midi aka Brussels-Zuid & night train for solo traveler

19:00 is just the tail end of the evening Rush hour. You should be perfectly fine. Just keep some awareness of your surroundings. There is security inside the station.

You may be taking a night train from Brussels-Midi, but 7 pm is not night, it’s early evening. You don’t mention when exactly you plan to take this train, but right now the sun doesn’t set until 9:30 pm, so it will still be light outside at 7 pm.
While the area around the train station isn’t the nicest part of Brussels, I have never felt unsafe there as a female solo traveler. I can’t help but feel that some of the stories you read online are exaggerated.
If I recall correctly the Leonidas shop is located inside the train station. I would not hesitate to go there and buy some delicious pralines.

Btw “danke” is the German word for Thanks. The Dutch/flemish word is “dank u wel”.

Agree that you will be OK, just keep an eye on your belongings, even on the train. Bag thieves will try to engage you in conversation while their accomplice will just take your bags. It can help to be in the same car as the conductor.

The good news is that the new government wants to 'clean up' the station and they recognise that social workers will need to be involved, not just law enforcement and cleaning crews. They also want to develop the area around the station with shops. If they succeed, it will be a big blessing for Brussels. They have been talking about this since 2023 but at the time all they did was move the problem on to other locations in Brussels, so it's not a simple fix.

Lavandula

If I recall correctly the Leonidas shop is located inside the train station.

That's not the outlet. The outlet factory offers chocolates at 50% discount, due to the minor imperfections that occur during the production of the chocolates. Here, you buy by the kilo.
https://maps.app.goo.gl/GjJ1rEgDA5APihTD6

I don't think it would be particular unsafe to walk there. You also can take the STIB bus line 73 or 78 from/to Midi station. The stop is called Petite Ìle / Klein Eiland.
There are luggage lockers inside the station.

Bag thieves will try to engage you in conversation while their accomplice will just take your bags. It can help to be in the same car as the conductor.

I think OP is talking about a nighttrain, not a regular train. Never heard of bag thieves on one of the nighttrains.

Dank u wel, all.
Yes this is for the night train to Vienna, travel in first half of October.
And Internet says the Leonida's outlet is about about a 15 minute walk from the station, which might be worth it for 50% off.
Hope I don't seem hysterical, because I can appreciate that some of these fears about Brussels Midi are overwrought. Maybe it has something to do with getting older and being more susceptible to apprehensions.

last time I stepped outside Midi the biggest danger was the traffic! And at 19:00 I don't expect it will be any better