Moving out as Tenant in California

I signed a one year lease on July 1st, 2025. The contract states that after 1 year, it'll become month to month. I still have not made a decision yet whether to move out or not, so I have not told the landlord on June 1st that I am interested in ending the lease, but planned to give him a one month notice.

Today, I wanted some clarification, so I called him and asked "If I was to move out on July 15th and give you notice on June 15th, will that be okay?" He said since I did not tell him on May 31st, I will owe the entire July rent even if I move out before July 31st. Then he told me he may find a tenant that wants to come in on July 31st, so when I told him will I be kicked out even if I paid for entire July, he said no. So I asked whether I can get refund for the remainder if he finds a tenant, he said he will only tell me after I give him an official one month notice.

I asked ChatGPT, and it says the owner's stance isn't that strong and that I can win in the small claims court. Is ChatGPT correct?

Thank you.