I have tried to install INotify inside a container of nextcloud following the instruction of instructions relink2013 posted on issue 197 but failed.
Please give me a pointer. 
Here is the actual result.
https://pastebin.com/yMt9m0q2
It looks like you tried to forcibly downgrade php to 8.1 and broke most things… I would suggest reading up on what the user posted in that GHI, checking in to what is in your container version, and then researching how to make them work together. Downgrading a core requirement to an unsupported version will not be a good idea, but i’m sure you COULD make it work if you wanted to.
It’s not something we will help with here though.