None of us said to run at max settings with no compression (not even possible).
We have given advice developed by many long time members here that play with these cameras and figure out the optimal sweet spot for performance.
It is up to you to decide what works best for you and what advice to listen to. But if you run too low bitrate, vbr, and h265 you will certainly have an event happen that your camera misses and then you will be posting to this forum asking how to improve the image....it has happened to many people...
Try it yourself and realize like most of us that the savings running h265 and vbr is no where near theoretical numbers. Mine was literally minutes difference so I go for the higher quality....
That has not been my experience. Typically when I do an audit or a customer says we were told we would get 45 days and we are not it's because cameras were left at h264. I remotely connect and change every camera to h265 and that alone drops the average bitrate by 20-30% overall. When I connect later that day the storage forecast reaches out that much further.
I'm not sure of what capabilities
Blue Iris has. Never used it, I only assume it's comparable. I know it is very DIY and it's not as well expensive but we use DW Spectrum and there are a lot of storage
tools that show you where your storage space is going and which cameras are using up all the disk space. It will forcast storage timeline based on bitrate usage over different amounts of time. Blue Iris could also do this? Not sure but probably. There is a very real difference between h264 and h265 though. I can say h265 didn't work that well with older software versions and it's greatly improved in the last 2 or so years.
As far as bitrate, it depends on what you're seeing. Indoor cameras don't need the bitrate max like an outdoor. Outdoor cameras don't need the bitrate if they're viewing a loading dock or employee entry. We rarely do residential but the cameras at my home need a little more because on a windy day all of the trees and hostas are blowing all over the place. It comes down to adjusting for the environment.
I also don't worry about VBR ramp up because the second it takes for that isn't going to make a difference.
LPR cameras are of course different. I run the 8192 on my 4mp LPR that only does h264 and it's CBR. But I do motion activated hi res recording with a 10 second pre/post buffer to help