Last year I got complimentary tickets for the 2021 year. Did anybody use them? It looks like I still need to make a reservation for a certain date but there is no such an option on a website.

Reservations are recommended. But they also have a will call window. There you can get your admission cleared. This happened to me as I purchased my ticket before the reservation date requirement. As long as you get there early enough(I got there at 9:30 and it opened at 9:00) they should be able to accommodate you. Good luck and enjoy.

You only have to make a reservation for an actual launch. You will be able to use your tickets just by showing up and paying $10 for parking. Then go to the entrance for a security check and they will scan your tickets.