It's an AMD card issue. I used to have an Nvidia 1070 before my current build and never had this problem. Ironically my Nvidia 1070 is better suited for DayZ than my AMD 7800xt lol. I've been doing some research on it and apparently it has to do with how AMD cards handle something called "Alpha To Coverage" or ATOC for short. I've found forum threads about this issue going back as far as 2012 for Arma 2. Apparently how Bohemia Interactive do ATOC really messes with AMD cards unfortunately, but there has to be a way to fix it. Maybe Bohemia Interactive and/or AMD will fix it some day because the game really looks ugly with foliage smoothing turned off :(

Still no news on a fix? I've been having this issue on my 7800xt. :(