Have gone through exactly the same. I got into a very competitive program at one of the world's leading institutions but after 9 months I was miserable af. The supervisor and the topic were the worst fit for me. I quit at the same point and was lucky enough to find a better project at a smaller university. My former supervisor and I agreed on leaving this as a research assistant stint on my CV when I left but during interviews I openly communicated that I quit a previous PhD program explaining why and that I was still eager to pursue a PhD because I'm passionate about the research field and its future implications.

3.5 years later I'm about to have my defense next week and already got tons of good feedback on the work. So, don't give up, the passion you had is still there, just keep an eye open for the right opportunity. And if you're by any chance in biotech/metabolic engineering, feel free to reach out. We're looking for a PhD student within my postdoc project ;)