According to this timeline S21, and S21plus suppose to get in December but in reality, the S21 series started to get One UI5. Even S22 series received in October but here is mention November
For day-to-day use, it's perfect not for heavy gamers but the casual game is okay. For me, it's best. Battery backup not that great need to charge once a day, as I don't do full charge only once a month. it's okay for me. The screen on time getting above 5to6 hour.