I was able to "hold breathe/steady aim" using dmr's and sniper on assault class. I did not try with with engineer or support. I do not recall the unnecessary indicator telling me I could do it while on assault though.
I too got the issue with the deploy beacon if near hill or on angle at start of round. It would disappear completely. my guess is it fell through the earth lol.
in regards to "vivid" there was an option to turn off the grain but I played on low settings withs a 10xx series gpu and FSR. I didn't have any concerns regarding vividity issues for vibrancy. I was getting like 80 fps lol