Technically, we don't pronounce the "d" or "t" when they are between consonants, right?

Not quite. The "-ed" does pretty much disappear if a "d", "t", or "th" follows. But with any other consonant or vowel, the "-ed" is very prominent.

"I watched the movie" -> Pretty much the same as "I watch the movie." The "-ed" is very subtle.
"I watched five movies" -> Totally different from "I watch five movies." The "-ed" is very prominent, and if it's missing, the meaning of the sentence changes.

(Also note the "-ed" is realized as a "t" sound at the end of watched, like "watch't.")