For software, it depends blender is a good source to create cartoony builds while roblox studio can do the same. You can work on low poly builds by also using Studio. Generally, all you have to do is use bright colors and the plastic material. Although this artwork can be accomplished in both whatever one is comfortable.
Creating low poly builds it involves Blender since it’s free and easy to learn as long as you practice and watch tutorials. I personally prefer Blender. Because it’s pretty simple to learn how to make. low-poly builds, however you can make low poly builds in Roblox Studio.
I find this topic has been talked about a few times but it’s just using different wording.