No words have the suffix -ez.
When words ending in s get a suffix (-e or -en), the s often turns into a z. Regardless of the reason, so both for simple plurals or because of inflection.
I guess it is simply because when adding the -e(n) the s will automatically be pronounced like a z.
Gendered nouns (masculine or femine) use the article de
and neuter (genderless) nouns use het
Besides gendered nouns plurals use de aswell
De vieze tafel
De vieze tafels
Een vieze tafel
Het vieze boek
De vieze boeken
As you can see (and ís explained in earlier lessons) all the adjectives receive the suffix -e, unless a word that usually is preceded by het (so a neuter singular word) is preceded by an indefinite article (een) then it doesn't get an e at the end.
The s turning into z doesn't have anything to do with its genderclass directly. It only has to do with getting a suffix.