I hate this movie but still have lingering unanswered questions...

I know I should have let this movie hang in the closet of forgotten memories, but I'm haunted by the unanswered questions that bog down on my mind like Luke's X-Wing in the Dagobah swamp.

I know most people probably don't have answers to these questions, but I imagine some feminist-fanboy who loves all things feminism probably shuffled through the leg-beard diaries of a mad screenwriter somewhere and found the clues to this unending cognitive scuffle that leeches onto my thoughts.

1) What the heck was the Rev-9? I assumed it was a nano-machine Terminator, but they literally never explained what it was or what its abilities were. Was it a cybernetic organism or was it just a very elaborate shape-shifting machine? They never bothered to explain it.

2) Why could the Rev-9 duplicate itself but only once and not twice or thrice over? It could duplicate itself and did so multiple times throughout the film, but they never explained why it didn't always have a duplicate or what the downside was of having a duplicate. Did it take power? Did it have a power source? Did the clone share the original's power source? They never bothered to explain.

3) Why was the Rev-9 invulnerable? Nothing seems to stop this thing. Not fire, not water, not explosions, not bullets, not even being crushed. I didn't understand the limits of this thing's abilities. Was it literally just impervious to everything short of a large scale microwave blast? And if a microwave blast was the only way to stop it, why didn't they suggest that earlier in the film?

4) What was the point of the human upgrades if they were only good for two to three minutes of combat? Grace explains that she went through the upgrade process but it only lasted for a couple of minutes and then her body would crash. If that happened in the battlefield then the upgrades were as good as dead. Worse yet, she couldn't even damage the darn Rev-9, so what was the point? If it weren't for Sarah showing up then Grace would have simply died. Somehow a 70-year-old geriatric woman was more effective than a physically augmented super-lesbian from the future.

5) Why did they want Dani dead? We were told that Dani was John Connor of her future, but they never said why. We were told repeatedly in the first two films that John was a great leader who led successful campaigns against Skynet's infrastructure and even managed to take over their time machine facility. In Dark Fate they literally never explained why Dani was humanity's best hope against the machines. If she were a hacker or computer whiz who came up with some kind of virus to disrupt their systems, then it would all make sense, but she was just a low-class factory worker from Mexico... WTF?

6) What was the point of the machines sending back a Rev-9 when they already seemed to be winning the war in the future and had even more advanced robots wiping out humanity? Those Tentacle Terminators were not only anti-air efficient but seemed to be capable of wiping out entire human platoons on their own. So why not send one of them back instead of the Rev-9?

7) I thought inorganic material couldn't be sent back through the machine, and if the Rev-9 is a nanomachine then wouldn't that mean its surface skin is still coated in inorganic material, thus rendering it incapable of traveling through time? This was also a plot-hole for the T-1000 in Terminator, but it seemed even more of a glaringly obvious problem in Dark Fate given that the Rev-9 had no weaknesses (opposite of the T-1000) and I didn't understand why it just didn't create a gun and shoot Dani to complete its mission.