That's a forum limitation. Nothing to do with your WiFi connection.It was just a picture I took with my phone and tried to upload it via "attach files" right here on the forum.
It's not possible to have 443 Mbps throughput with a 433 Mbps link rate. So something is wrong with your "before" downlink comparison number.
As I said, the speeds you now report are reasonable for a 433 Mbps link. If you want higher speeds, upgrade your laptop adapter.