First time HC midway through elite would like some tips

hey im trying to get the hardcore achievements to 100% the game,and would like some input from more experienced players.
its my first time playing HC and been a pretty smooth sailing so far with building extremely defensive while also being a pet build on top.
what i would like to know is what are some known run killers i should be aware of in advance, i really fear of reaching a point where i just get one shotted out of no where and losing my character which i put a lot of time and effort into.
also any tips about how to improve the build or what to strive for would be appreciated.
link to character: Ritualist, Level 70 (GD - Grim Dawn Build Calculator

Might want to hold off on that if you plan to get the new expansion when it releases some time in 2024 all being well. From the dev stream at the end of August.

New achievements coming, some for Ascendant mode.

this is exactly what got me back into the game i want to finish 100% it in preparation for the expac =)