Sorry, I do not agree. In general liaison is not done after a verb or a noun.
The Z liaison after "avons" is optional, but welcome.
Certain endings typically indicate the gender. There's a simplified as well as an elaborated list on this webpage that can help you with the same: https://frenchtogether.com/french-nouns-gender/#A_simplified_list_of_endings
Of course, there are exceptions. But that's the case with any language.