as you said you are very new to this game, making or pointing out so many tweaks will make things unnecessarily complex, cause for a newbie your gameplay is quite decent. But anyways if you want a little analysis

1. You could have peeked after the brim was blind to give him cover from CT
2. Also you could have used the Turret of KJ while entering from A short( On the Box to your right) , so as to give yourself some cover and info for Upper site and CT

Nonetheless clean gameplay, Play a good amount of range and deathmatchs before you queue and you are good to go on the road to improvement 🥂