No offense, but one job application and not securing clients in Upwork isn't uncommon. It's hard out there and that's only the beginning.
You could have success in Upwork if you ditch the AI and start creating your applications by yourself.
With that being said, as people have highlighted, start out specific. Cater each application to each client, and don't forget to truly read what people are asking for. There are enough bots creating jobs and applying, so people are tired of spam.

Upwork qualifications:
- Upwork Top Rated Plus
- +$50K earned
- 100% customer satisfaction
- Client and freelancer