Update via iTunes after backing up your data.
Let them index within 72h, and you'll have a real look.
For me, iOs 10.3.3 is still better iOs 11 a little bit (battery life), just wait to ver 11.2 or 11.3
From 6S to higher, it'll be ok but on 5S and 6 (6+), still lag and delay when you make some actions.
