I have read your long question. It is a story about how a society of women ended up as strong as the men. If the only question you want answered is indeed "Is this 900 page story believable?" then your question is simply unsuitable for this website.

If you are prepared to trim down the question to be suitable, then you can start be (a) removing the less important parts of the story and (b) focusing on the most difficult parts of the question. Here are what two of your paragraphs look like when trimmed down:

Girls/Women beating muscular men and monsters in fights and women fighting alongside men in wars. These are two very is a common trope in fiction that we’ve seen time and time again in fantasy and sci-fi, but while sci-fi has the excuse of using technological weaponry and biomechanical augmentations to reduce the huge gap in physical strength between the two sexes, fantasy almost always relies on boring old magic to make the idea of women fighting in wars and not immediately dying/hindering the efficiency of her comrades plausible. My world has this trope but I would like it to be scientifically plausible.

One day out of nowhere, a large steel capsule crashed into Earth near the home of this male-dominated tribe. The males forcefully opened it but would end up regretting it. For inside of this capsule was a artificial virus designed by a race of creatures that existed far, far away from Earth on another planet (it’s basically alien technology). Earth was attacked by a virus that seemed to only affect male organisms (what do you think sounds more realistic. A male-only virus or a male human-only virus?) and within a single year, almost all of the males/men in the tribe died. The virus found its way into almost every corner of the planet and killed off 90% of all male humans/male-life on Earth. Before it was able to finish off the remaining 10% of men/male-organisms however, the Gods of my world stepped in and used their nature powers to kill it for good. The impact of the virus was still immense though, as 90% of the males/men on Earth were now deceased, and now the surviving women in the tribe , who had taken the few surviving men in the tribe as prisoners and were now being led by the only woman in the tribe with knowledge of how to hunt, fight and create traps, were forced to live like their male oppressors in order to survive. They learned to hunt, fight and create traps

As you see most of the text can be removed. Try for yourself.

Don't Ask a Really Big Question

I have read your really big question. It is a story about how a society of women ended up as strong as the men. If the only question you want answered is indeed "Is this 900 word story believable?" then your question is simply unsuitable for this website.

If you are prepared to trim down the question to be suitable, then you can start by (a) removing the less important parts of the story and (b) focusing on the most difficult parts of the question. Here are what two of your paragraphs look like when trimmed down:

Girls/Women beating muscular men and monsters in fights and women fighting alongside men in wars. These are two very is a common trope in fiction that we’ve seen time and time again in fantasy and sci-fi, but while sci-fi has the excuse of using technological weaponry and biomechanical augmentations to reduce the huge gap in physical strength between the two sexes, fantasy almost always relies on boring old magic to make the idea of women fighting in wars and not immediately dying/hindering the efficiency of her comrades plausible. My world has this trope but I would like it to be scientifically plausible.

Or just:

Women beating muscular men and monsters in fights is a common trope in fiction. My world has this trope but I would like it to be scientifically plausible.

Second example paragraph:

One day out of nowhere, a large steel capsule crashed into Earth near the home of this male-dominated tribe. The males forcefully opened it but would end up regretting it. For inside of this capsule was a artificial virus designed by a race of creatures that existed far, far away from Earth on another planet (it’s basically alien technology). Earth was attacked by a virus that seemed to only affect male organisms (what do you think sounds more realistic. A male-only virus or a male human-only virus?) and within a single year, almost all of the males/men in the tribe died. The virus found its way into almost every corner of the planet and killed off 90% of all male humans/male-life on Earth. Before it was able to finish off the remaining 10% of men/male-organisms however, the Gods of my world stepped in and used their nature powers to kill it for good. The impact of the virus was still immense though, as 90% of the males/men on Earth were now deceased, and now the surviving women in the tribe , who had taken the few surviving men in the tribe as prisoners and were now being led by the only woman in the tribe with knowledge of how to hunt, fight and create traps, were forced to live like their male oppressors in order to survive. They learned to hunt, fight and create traps

Or just:

Earth was attacked by a virus that killed off 90% of all male humans/male-life on Earth. The surviving women in the tribe were forced to live like their male oppressors in order to survive. They learned to hunt, fight and create traps

As you see most of the text can be removed. Try for yourself.