Is it too late for me to do a PhD in the US?

In 2019 I started an integrated Masters of Physics at Oxford. Graduated summer of 2023. During that time I first authored an AI research paper with the Oxford AI Society. We tried to get it into ICLR but it got rejected. Managed to get it into a NeurIPS workshop though, however I'm unsure if that holds much weight. The paper also got 21 citations on arxiv which is nice.

After graduating, my gf and I broke up (mutually, long distance was too much) and life after university made me quite down. Bad market and struggled to get a job. A friend reached out to me about doing a startup in San Francisco. Did that startup until January 2024 when I quit because I had no money left.

Through the connections I made out there I landed a gig at Chroma DB. Did a research contract with them. We didn't make a paper but instead made a technical report. The GitHub repo for the project has gained over 200 stars. However, since I was remote and US visas are a pain, my contract wasn't renewed.

I tried starting my own business from July 2024 till December. I managed to secure a long term contract with a US construction company building them software that automates admin via GPT. Still doing this contract now and they've said they're happy to keep me for as long as I want.

That's the context. During the winter of 2024 I thought heavily about applying for a PhD in the US. At: CMU, Stanford, Berkeley, MIT, CalTech, etc. However, I knew my profile wasn't strong enough. So I want to apply the winter of 2025.

I'm in talks with a few institutions and research groups about doing projects. But is it possible that, starting in February 2025, I can co-author, submit and have accepted a paper into a top conference by December 2025? I feel like I'm too late to this decision and should have skipped that San Francisco startup to just do research projects from the start.