I had a similar experience with copy,ai and Jasper/Jarvis. The quality of output is just not great. I know it's not supposed to be a total solution to content, but they output seems t ohave gone downhill.
I built a custom tool for generating blog posts using OpenAI (Davinci) with my own prompt. All I did was clone the OpenAi started app from Github, make some edits to the prompt, the index.js file, and that's it. I made a tutorial on how to do this but I'm still editing the video. I'll post it on BHW when it's done. Btw, I'm not a coder at all, I just copy/pasted and used vscode to deploy the app locally. Then I paid a dude from Upwork $80 to deploy it to a domain.
Another cool tool is Riku,ai. You build your own prompts and use your own API keys for the different AI models out there. It support OpenAi, Cohere, Ai21, and GPT-J is free unlimited use. If you learn how to build prompts you make the AI basically output good quality stuff.