Regarding this issue I contacted Bohemia Interactive support directly, I received some information that could possibly fix the error, but did not fix mine (unfortunately). The first solution they replied with was this:
" Hello, do you use any custom mods? Please try clean reinstallation of Arma 3: 1. Uninstall the game. 2. Make a backup of Arma 3 folder in Documents. 3. Delete both Arma 3 folders in Documents and Steam: \Users\*YOUR USERNAME*\Documents\Arma 3 \Program Files (x86)\Steam\SteamApps\common\Arma 3 4. Reboot your PC. 5. Run Steam as Admin, download the game. 6. Try to run Arma 3 (without mods). This should fix your issue. "
Since that didn't work, I notified them of this and received an email saying this:
" Hello,
please try to use custom memory allocator for Arma 3: https://community.bistudio.com/wiki/Arma_3:_Custom_Memory_Allocator Thank you. "
It might work for you, it might not. Neither solutions worked for me unfortunately but I did do something that fixed the issue temporarily,
First, go to \Users\*YOUR USERNAME*\Documents\Arma 3 and then delete both the "Saved" folder and the "Arma3.cfg" file. Both of these files regenerate when you next launch Arma 3 although your video settings will reset to default. Also for some very strange reason, increasing my video settings actually reduced the chance of this happening, quite dramatically. I know, there is no logic in this but it worked for me temporarily (Around 6-8 hours). Although I have also found that if I reinstall the game, it works the first time I launch it but then the issue occurs the 2nd time I launch Arma 3. Some people also say that creating a new Windows profile or Arma 3 profile works, but once again, worked once and never again. If I find a permanent solution I'll post it here, and I'll also post here any information I get from Bohemia Interactive support.
PS. @steve88 the stages of my crash are 100% exactly the same as yours. Although I do know everyone's PC is different, if we are both having the EXACT same issue, it might not work for you. (Sorry :c)
EDIT: Also if you spawn in an enclosed area (A building) or just somewhere where you aren't open and can't see a ton of objects this sometimes stops the issue from occuring when you first login to the server. So if possible, try and get a PC that works without this error, and when you logout, logout somewhere like a building. Just a friendly tip :)