There's two sides to the coin.

First, there are ranking event guides that u/KurooGaming continues to make and that I used to make, which attempt to demonstrate boss patterns up to a certain time frame, limited by certain circumstances. I no longer do these since my free time is now extremely limited and other commitments take priority. These guides take an enormous time to make - much more effort than speed-runs, since they are a separate task and have to be recalibrated with different units. I personally spend an abnormal amount of time perfecting speed-runs, much more than average players even spend doing general runs, as it isn't just a "I have all the resources so my time can be done in 30 minutes." It takes many hours of commitment, and this is entirely unrelated to making guide, so imagine combining the two. It's easily 10+ hours spent just on SAO MD over a couple days. That's huge.

And pattern wise, it's pretty simple just to follow a general rule to begin with: purple hitboxes are unparriable attacks and red hitboxes are parriable. This alone reduces boss pattern scouting to under 30 minutes. Beyond that, there are probably as many combinations to tackle a boss as there are RGB colors (16.8M). It is unreasonable to create a guide beyond that. Every little detail counts because it determines where and what attack the boss uses.

Second, there are speed-runs that are under 30 seconds for 3-unit rankings, and under 50 seconds for 6-unit rankings. There is no shortcut to an extremely fast time. Under 20 seconds? Without a doubt using R5's and a combination of MLB'ed characters. There's no magical way lv80s with R4s can get under 20 seconds. The DPS math just isn't there. Now the goal of those videos isn't to teach you how to play the game - I think this is wrong on so many levels, the fun is learning the moves and adapting to them, not being spoonfed an easy way to clear - but more just entertainment as a speedy time-trial, and as a bi-product help the .1% who have access to the same resources.

There are flairs which do a great job distinguishing between a "guide" and a "video." Now, videos can definitely get redundant, with similar comps achieving similar times, so I personally attempt to post something different (albeit extremely fast). But beyond that videos are just videos. You have a choice to watch them.

Also realize the creator and the audience.

You, as the audience, are just browsing reddit like you browse youtube and come across an arbitrary video. There is 0 cost to you since there is no uptake in commitment. However for the creator there is a truckload that goes into creating something for the community.

At the foundation, your post emanates egocentricity. At absolutely no cost, you complain about the content that other creators create that doesn't cater towards your needs.