Hello, I am not really sure how to play the game or what to do at this point.
First off, I'm on the PS4 version, so there's basically no multiplayer. I've literally never found a multiplayer match anywhere from level 1 - Paragon 500, on any difficulty, in any game mode.
I have full Inarius, and some other 'core' build items which enabled me to clear the Grift 70 to unlock Primals. I only have two ancients, though - my Shadowhook and my Unity.
My only understanding of how to progress at this point is that I basically need to upgrade all my items to ancients, and ultimately primals. I also have the ability to add a 7th modifier of Int to each ancient or primal piece in the cube. This requires super high level gems. And to try to get ancient / primal items on my own, in addition to farming, I can gamble them with Kadala and reroll in the cube for 50 souls and 25 bounty mats. So, the only thing I understand is that all of these are priorities:
1 - Keep a large stock of bounty mats, which enables me to constantly reroll items to try to get them ancient or primal. This requires me to run bounties every once in a while when I'm low, preferably on T13 if I can clear that high.
2 - Keep a large stock of high level gems, which requires me to constantly clear high level grifts which I struggle with because I don't yet have the required gear
3 - Run normal rifts to stockpile gear and DB's and normal gems and FS's to help with both of the above
So is that it? I basically just run all 3 of these in whatever fashion I feel is best, based on what I'm low on at the time?
But what is the best way to just try to get new items? Is it chain running normal rifts because I get a ton of gold and DB's and even though I might only get 1-2 less legs per run than a Grift, it's worth it from a time standpoint? What is the benefit of a grift beyond leveling up gems? Yes, I've gotten some good experience, but at Paragon 500 I already largely have all the bonus stats that will help. Gaining some additional gold find at level 631 is meaningless. And I've never gotten the impression Grifts are good for loot. I've averaged something like 8-10 legs per T13 normal rift, and I get maybe 3-5 per Grift, when I do them in the 60s.
What about seasons? I played Season 10 and had a DH and my season stash has about 250 legs. Do I just salvage them before they expire? Is there any incentive to play Season 11? Doesn't really make sense to me ... can't I just use a Gem of Ease with 500 Paragon Levels and get a guy to 70 in an hour? And then he/she has access to all my gear / crafting mats / Paragon levels / etc.?
So, assuming you're not doing multiplayer, the only valid reason to desire to do seasons is for the GR leaderboards. Also, you start seasons fresh - seasonal characters have access to nothing from your other characters. No gem of ease, no crafting mats, no paragon levels, no gear. You start at level 1 and with nothing.
You seem to have a good idea on how to progress your character. To answer the question on "what is the best way to just try to get new items?" the answer is definitely by running GRs quickly. Set up a build to clear through regular rifts as fast as you possibly can to get GR keys, then use the GR keys to clear the highest GR you can reliably run in ~8 mins and under.
Doing bounties for rerolling of stuff is important for weapons and other highly important pieces - less so for more common/less important pieces of gear. A great example of this is that rerolling a Karlei's point for demon hunter is a bit less good on the basis that upgrading daggers via regular mats will get you a karlei's half the time - you can effectively "reroll" a karlei's for the cost of 2 rare upgrades rather than one reroll.
So I've been chain clearing Grift 55 (still have 60 tokens) and it takes anywhere from 4.5 to 6.5 minutes based on shrines, I typically don't die. Now I'm wondering after reading these responses ... if I'm going to stockpile a ton of resources, and they can be used on any character, and I can get a Wiz or DH to 70 in an hour and then it has all the paragon points ... why invest it in the Necro? Yea, it's fun, but it's not a top tier class and I haven't invested too much into it. Once it comes time to start pouring in thousands of souls to recraft legs, I'd rather do it on a character that I can clear REALLY quickly with. And on that note, I don't even think Inarius is the best anymore? So I'm currently hunting for ancient Inarius which might not even be optimal just for my class, let alone overall.
Why 8 minutes or under? That would put me at the point where I'm probably dying at least once, which takes away an upgrade, and would also seem less optimal. And if it's only going from 55 to something like 60, that can't possibly be worth it in terms of gear.
I'm currently doing 4 Grift 70s, then logging on my freshly rolled 70 Wizard and gambling to get set pieces. Once I have the Tal Rasha / Vyr setup, I'll probably swap. Necro is / was fun, but let's face it. It's about speed. Reminds me of years ago in WotLK when my friend would grind out rep mats with his Shadow Priest ... while I cleared twice as fast with a Mage. Just isn't a point to play anything sub-optimal when this game is all about chain farming things as quickly as possible.