Protip: you can come in to Brussels through Amsterdam. Passport control line in AMS is negligible (at least at 5AM, though I'm sure it's not  too bad at other times either), and it's only a 2h train ride straight from the AMS airport to Brussels.

Interesting tip! Amsterdam's airport is definitely a well-organized hub. If you're an early riser, this could save you a lot of time and hassle. Plus, a scenic train ride to Brussels sounds like a nice bonus. Always good to have more efficient travel options in the toolkit!