nesting folders

We all have our OCD issues to one degree or another. Mine is aligning the sippy part of my coffee mug lid with the logo of the coffee cup. Drives me crazy if they are misaligned. :-)

Folders on my iPhone however, aren't included in my OCD issues!

That’s not a feature of iOS, but it sounds like a good idea. Let Apple know: https://apple.com/feedback.

You do know that a folder can have several pages, so as a workaround you could break down your content onto different pages of the folder, such as a page for rentals, another for hotels, etc. I already do that.

Given what you want to do based on your response to Lawrence, you clearly can't avoid having more than 1 home screen.

I agree with Lawrence however that your idea is a good one and you should provide feedback to Apple via the link he provided.

Well since you can't do that, you can have folders on more than just one home screen. You are not limited to just one home screen. As mentioned, you can 11 home screens with 24 folders on each screen, each containing up to 135 applications.

This link might help you --> How to move apps and create folders on your iPhone, iPad, or iPod touch - Apple Support

Unfortunately, you cannot place a folder of apps inside a folder of apps. You can add more apps to a folder, so you may need to reconfigure some of your folders to be perhaps broader and hold more applications as a possible solution. You can, I believe, hold up to 135 apps in a single folder. How many pages of folders do you have on your phone? You can have up to 11 home screen pages. Are you saying you currently have 11 pages of just folders, containing multiple apps in each folder?