That is a huge load for a single switch in a residential layout. Are you sure they are 50 W each? Not “50W equivalent”? Those would be super bright.
Anyway, Leviton makes a zwave plus dimmer switch that can handle up to 450 W of LEDs. ( Note That the ratings for an LED load, or “non resistant load,” are always much much lower than the ratings for an incandescent load because the physics are different. LEDs have a very large current surge when first turned on, called “inrush current,“ before they drop back down to their regular operating load and the switch has to be able to handle that.)
https://store.leviton.com/collections/z-wave/products/decora-smart-1000w-dimmer-with-z-wave-technology-dz1kd-1bz?variant=33943254147
Shop around, because most retailers will have it for less than the manufacturer’s site:
https://www.amazon.com/Leviton-DZ1KD-1BZ-Decora-Dimmer-Technology/dp/B01MQX5L8P
This model, Dz1KD, is also on the official “works with smartthings“ list.
https://www.smartthings.com/products/leviton-leviton-z-wave-dimmer-in-wall-dz1kd
a “50 watt equivalent LED” typically has a draw of 7 to 9 W. And the brightness of around 400 lm.
A 50 W LED would usually have a brightness of 4000 lm, and would normally only be used for photography, grow lights, nighttime construction projects, warehouses, gyms, and some aquarium set ups. Or the security system at an auto dealership. Almost always described as “super bright.“ But check the specs.
Example of 50 watt equivalent floodlight
https://www.amazon.com/AmazonBasics-Commercial-50-Watt-Equivalent-Dimmable/dp/B079VP22QY/
Example of 50W LED floodlight
https://www.amazon.com/Lighting-Warehouse-Industrial-6000-6500K-Commercial/dp/B07GK183B3/