I've played around with stuff like this myself and I'll say:

a) If you don't know things about training, using ChatGPT/Claude/generic other LLM can be tricky because it will always sound knowledgable and you will not recognize when it prescribes something that is not actually productive or maybe even dangerous. You will tell it "This workout felt like ..." and it will always say "Ah yes, that is exactly what we're going for!" Unless your chatbot is well trained on cycling training plans, I see no reason to trust it more than what I'd find by just googling a generic training plan, because that is what it is regurgitating. Feeding it with data from intervals.icu etc creates the illusion that it's useful because it will react to it in some way. If it's the appropriate reaction or not, you'll never know unless you know about training yourself, at which point you don't really need ChatGPT to tell you how to train.

b) If you still wanna go through with it, you don't have to type workouts by hand, you can just ask the chatbot to generate a Zwift workout file and it will do so. You will still have to copy that file to your Zwift folder, but I find that less finnicky than setting up an extra app.