1040-X | 1040-NR

I got a couple of questions:

1. I was on F-1 (Student) visa during 2023. I am working as a software engineer as part of my Optional Practical Training. I am a citizen of India. I claimed itemized deductions during 2023. Was I eligible for claiming Standard Deductions under Article 21 of US India Tax treaty agreement? if yes, I can do it using a amended tax return?
2. I changed my visa status from F-1 to H1B from October 2024 onwards. Am I considered as Non Resident while filing my tax. Can I also claim standard deductions (Article 21 of US India Tax treaty agreement) for 2024 tax filings as well?