don't worry its completely normal for a phone to experience some lag (sometimes bug which sadly wont be fixed until next upate) and battery drain after a major update for a week before your phone calibrates to your usage.

apna maa ka chus sale pajeetey

Its not Samsung its **bleep** optimization, bugs, glitches on Instagram on androidMeta apps runs like **bleep** compared to iOS on andriod

how? and is it really necessary?

brother this is not a bug i did it myself on goodlock plus it looks way more visually pleasing than default samsung keyboard look