The noun influx can be countable or uncountable. In more general, commonly used, contexts, the plural form will also be influx. However, in more specific contexts, the plural form can also be influxes e.g. in reference to various types of influxes or a collection of influxes.

What is the plural of monogamy?

monogamy (countable and uncountable, plural monogamies) A form of sexual bonding involving a permanent pair bond between two beings.

What is the meaning of influxes?

: the arrival of a large number of people. : the arrival or inward flow of a large amount of something (such as money)