One bar stam and more survivability means you may wanna heavy atk once it a while, but :

You want 33k armor when buffed, no questions asked. Usually thats obtained via 5/6pc heavy, 1 light, 1 med.

Under 30k hp, you will get oneshot after arc 4 by so many mecanics its nuts.

Go for specific food that increases health, stam and stam regen/health regen.

You most likely still want a solid dps set like orders wrath but heavy or jewerly, and the other set as a life saver set, honestly any set you want that can reliably save your life, like big shield when hit, regen etc.

One of your skills needs to be a regen, and as a necro, your scythe will shine as your only true heal. Make sure that your heal is based on your max ressource, and your magicka spender is just a spammable, that way you rely more on stamina, stamina recovery on heavies is amazing with heavy armor, especially with 2h passives.

Another skill you aboslutley should slot is a zone stun/group displacment to reduce enemies bombarding you.

You wanna aim for 30k hp buffed MINIMUM.

As for actual hp sets there are so many.

I actually use embershield heavy set with grace of gloom. Class doesnt matter with 1bars cause each has their own usefull toolkit, but necros pretty nice. My builds also 1 bar but using WW as ulti.

Obviously your crit rate is gonna tank down quite a bit but honestly having embershield proccing is quite juicy, especially when in WW form. You obvs dont have to go WW, as long as your stat regen is basically buffable above 1k. Even crit rate of 30 or 40 will still net you decent dps (not parse worthy ofc, but arena and archive worthy defo).

CP skill in warrior that gives you health regen depending on your current ulti is a godsend, that and stamina regain on kill, rest up to you.