You’ve not mentioned where in the world you are, which will affect what products are available for you.
In wall dimmer modules, such as the Aeon Labs Aeotec Z-Wave Micro Dimmer, 2nd Edition (DSC27103-ZWUS), are used one per load. In 3-way(n-way) switch applications, only one would be used, not one fore every switch. These modules will be a tight fit in a 14CuIn gang box, such as yours, but they should fit.
There are also Z_Wave dimmer switches, such as the GE Z-Wave Wireless Lighting Control Dimmer Switch, that will fit in these gang boxes. Though, again, it will be snug. You’ll want to look into the the Instant Status feature and what it is used for. This GE switch does not support Instant Status.