Files with red warning sign and not being given the option to "Apply to all enclosed"

I have been having some issues on my work mac laptop.

Firstly, I was experiencing problems with WIFI connectivity - and then I wasn't able to save any new downloads/docs as I would receive a warning that "file cannot be saved because it doesn't exist".

After going through the comments on help pages I realised this could be a Pathway problem and so I followed instructions to create and save a new TextEdit doc by going all the way through my files to the very top level folder on my mac - to then navigate downwards through the folders I wanted the doc to finally be saved in.

It was here I realised most of my files had a red warning sign with a white line through the middle. I googled what this issue could be and again was referred to go through Finder - top level folder (name of the MAC) - users - and then could find the files with the red symbol - right click - get info - change the settings at the bottom to allow 'everyone' to be able to 'read and write' - HOWEVER now I have came to a new issue where I do not have the option when choosing the gear symbol to 'Apply this to all enclosed', as the help guides suggest, and I am only left with the option to 'revert changes' if i wish.

So I'm looking for help on how to gain permissions back to these files, and will this finally resolve the issue I am having with saving files and them 'not existing'????