tank crash?

Hi all, I'll try to not ramble on, but my tank has been in a downward spiral for 3 or 4 weeks now, and I am really struggling to find out what to do here. Tank is a Fluval Evo 13.5, running since 7-25-2021. Light is a Fluval Marine LED 3.0, Sicce Syncra Silent 1.0, AI Nero 3, InTank Chamber 1...

So in the last two weeks my tank has gone from great to bad my female mandarin starved (out competed by male) my acropora colony bleached / turned almost completely white I'm not sure why my stylophora frag bleached / turned almost completely white I'm not sure why my torch coral has lost...