In the current circumstances, only persons travelling themselves or having travelled and airport staff are admitted to the terminal. People accompanying wheelchair users or minors can also access the terminal.
However, all this means that it is not possible for someone to come wait for you in the arrival hall. Ask your friends and/or relatives to wait for you outside in the designated areas at arrival level. As a passenger, you can find these zones by following the signage towards "pick up zone friends & relatives".
You can park in the nearby car parks P1 or P2 across the terminal. You pay €2 per half hour for up to an hour. And with the Brussels Airport Pcard + you can even park for the first 30 minutes free of charge.
Taxis are, as always, available when you leave the arrivals hall.
If you go home or to your destination with professional transport (e.g. arranged by the hotel), they will also be waiting for you outside. They will pick you up at the blue coloured zone on the bus station level (0). The easiest way is to follow the bus icon signage. This bus park is better known as "P15" among the drivers.