Tax Status for Third-year J1 Visa in the US

I came to the US in 2018 with a J1 visa as a research scholar. I lived in the US for 365 days in 2020 and undoubtedly I became a resident alien. So when I file the tax return for 2020, should I do as a resident alien for the whole year? Or should I file it with dual-status (183 days for NRA and the other 183 days for RA in 2020)?

Thanks!