If you're looking for something other than Soundify, there are a few options that could work for you.
AISound Copilot is a more powerful alternative that lets you generate unlimited amounts of AI-created sound effects for videos and games. It lets you generate SFX instantly by uploading video, with detailed text prompts and royalty-free sound effects. It's good for people who want to create their own sound effects without having to license them or search for them.
Audiobox is another good option, particularly if you want to synthesize voices and sound effects from voice input and natural language text prompts. It offers models like Audiobox Speech and Audiobox Sound that can generate audio from text prompts or audio samples, and that can edit audio to remove background noise or replace parts. It's geared as a creative and experimental tool, so it's good for generating new audio material.
If your needs are more musical, Soundry AI offers a generative toolset for musicians that includes text-to-sound abilities and unlimited sample packs. The platform lets artists create music more easily by generating sound samples based on text prompts and offering an interface that's easy to use. It's free to get started, but you can sign up for artist partnerships to contribute to the AI model.