You need a new one. STR / VIT / 6% CHC / Socket
Re-roll the Furious Charge damage to 15% Rend damage
Ideally, you want a new one. STR / VIT / All Resist / 15% Life or Life Per Fury Spent. You need a high value on the legendary affix, i.e. preferably above 145% Rend. For the one you have now, reroll the Bash damage to Life Per Fury Spent.
Reroll Cleave damage to VIT but you need new ones. STR / VIT / All Resist.
Reroll Hammer of the Ancients damage to Armour but you need new ones. STR / VIT / All Resist / Armour.
Reroll Call of the Ancients damage to 8% CDR
Reroll VIT to 20% AD or 8% CDR
You need a new one of these, but this is one of the single most difficult items in-game to get a good one of. Anything that gives you a CHC / CHD combo will be a massive improvement over your current one.
Reroll Life Per Hit to 20% Physical damage but you need new ones. STR / VIT / 6% CHC / 20% Physical.
Ring 1 - CoE
This one’s fine for now. STR / CHC / CHD is fine.
Ring 2 - ORotZ
Ideally, you’d want to be wearing a BoM, as it can come with STR / CHC / CHD, and you’d cube the ORotZ, due to the fact that it has fixed affixes, most of which are not useful to the build.
Istvan’s Paird Blades are a good choice for pushing, but for speedfarming, Bul Kathos weapons are preferable. As for your current blades, if the sockets were added by re-rolling at the Mystic, and you have some Ramaladni’s Gifts available, roll the sockets back into useful affixes, e.g. CDR for easier up-time on WotB, or 24% AD, and then re-add the sockets using the gifts.
Oh, and you should put the ancient in your main hand (the left slot on your character sheet). For automatically cast Rends (caused by Lamentation) it’s irrelevant as damage alternates between the main hand and off hand weapons, but for manually, hard-cast Rends these come from your main hand’s weapon damage, so you want the higher damage weapon in your main hand.
Cube - Armour Slot
Stone Gauntlets, unless you can absolutely maintain 100% up-time on WotB to counteract the slowing effects, isn’t a good choice. Better options would be Mantle of Channelling (25% damage and 25% mitigation) or Aquila Cuirass (50% mitigation).
Follower - Templar’s gear
Weapon - Thunderfury
Shield - Freeze of Deflection
Amulet - The Ess of Johan
Ring 1 - Wyrdward
Ring 2 - Oculus Ring
Relic - Enchanting Favour
Ancients are 1 in 10 legendaries, and primals are 1 in 400 legendaries. So, to maximise the number of ancients and primals you get the best way is to maximise the number of legendaries you get. That means speed-running T16 nephalem rifts for keys (and you’ll also get some Death’s Breaths for rerolling at the Mystic) and the highest GR level you can manage where it takes you no more than 3-4 minutes per run. You’ll get a lot of legendaries this way.
Well, it’s 4.5% right now so you still have 1.5% CHC available. Concentrate on replacing the other pieces I mentioned first. The helm you have now is pretty decent. It’s ancient, can get to 6% CHC and has a pretty good roll on the STR affix.
Until you reach that point that all of your items are great, and I mean even the secondary stats are good, and have a tone of main stat ( strength in your case), it doesn’t hurt to invest a couple of hundreds paragon points into vitality. Personally I feel comfortable when I have at least 600-700k life with whatever class I play, for high GRs but I also have almost 3k paragon so I can afford to spend 150-200 of them into vitality.
Also try to favor all resistances instead of armor for your items where you can get it. Torso, pants, boots. Armor scales with strength or dexterity and all resist with intelligence and since you are a strength class you ll get plenty of armor from paragons and gear anyway. That’s why you also need to place diamonds in your pants and torso slots. The exact opposite would be if you were playing an intelligence character. Then you 'd need armor more than all resist. Although don’t ever sacrifice an offensive stat for that. Only if it comes to which one of those two you can pick. So for example don’t ever roll rend damage from your torso into all resist. But if your pants for example have strength vitality and armor then you can replace armor with all resistances.