Don't look at number of options, look at number of seats. Would you rather have 100 oversold flights, or one wide open plane?

On UA, I'm not seeing anything on the 19th or 20th to AMS. There are quite a few seats from IAH on the 18th in J, but it's still early to know if they'll stay.

Just to get you across the ocean, ORD-BRU is also decent on the 19th, or there are lots of options to LHR.