How do I progress my RF Chieftain?

I just started playing this game a bit over a week ago and went with the recommendation to play Pohx's RF Chieftain as a first character. Throughout the campaign it was great, I never died and it went really smooth.
Right now I am progressing the Atlas, currently on yellow maps. I got the first red ones but I didn't try those so far because T10 already gives me some trouble.

My characters are set to public. I would be really grateful if someone could take a look at it and tell me what I should improve. After feeling really squishy early in white maps I spent like 10 chaos orbs to fix my chaos res from -60% to 75% and haven't changed my gear since. With auras on I am at 87% all elemental res, 75% chaos res, 62% physical and 4,5k health but I still get instantly deleted by a lot of things, especially packs of skeleton mages and some rares. Sometimes I open a strongbox or a crop in harvest and instantly die. Right now at level 89 occasional deaths are enough to completely stop any progress in leveling further up.

What should I improve in regards to my gear to be able to progress further? I know that my weapon is bad and I need a 6-link and I guess I'll get there eventually. A big problem is currency. When running yellow maps I get like 1 chaos orb in 3 maps but significant upgrades will cost several divines. Right now I have close to 50 chaos I could spend on recommended upgrades.

I would appreaciate any kind of advice. My goal for the remainder of the league is to get 36 challenges done and 115 atlas points. I don't know if this is possible as a new player with zero experience but I'll try.