How fast after the end of a strike does the Belgium railways return to a more or less reliable schedule?

The reason for the strike ending at 22h is so they can attempt to get all the material at the required destinations for the next day, e.g. they need x amount of trains in Gent or Oostende so they can handle the morning traffic the next day. Note that this is not a guarantee for success, I've often experienced delays the day after a strike because not all trains were available or even "complete".

Expecting to get a ride after 22h is unwise, since most likely there will be no personnel available to "accompany" the train (checking tickets etc.) since these people often use the train to arrive at the trains they're supposed to accompany. In the past year I've often experienced some delay because there was supposed to be a replacement driver available in the station for the train I was taking, but he was delayed because his train had a delay.

Make sure you have different means of transport. It is very doubtful that you will see a train that day. I suggest you take a cab, at that hour there shouldn't be too much traffic. And it's not too hard to get one in Brussels.