Not sure if still a thing but this has happened to me multiple times over the years:
random note, its not "Ubuntu" permissions, but, rather, "Linux" permissions.
Same permission system that your phone uses too. Even iPhone, has the same underlying permission system.
Once, it "clicks" though, they are extremely simple.
And it is a VERY simple model. But if you come from windown, it might seem hard and cumbersome.
Spend some time making sure you understand it, and you'll save youself a bunch of issues in the future.
To be fair the windows model is more or less "Yes mr ransomware developer, you can do whatever you want"
"You need admin privileges to d"- Ok sure.
Understanding the meaning of the permissions is easy.
The problem arises when programs created by someone else make use of other UIDs and GIDs without properly documenting it.
Permissions are a great example of they're impossible until they're easy.
The reason you're seeing people say they're easy is because they get permissions. They mindset where linux permissions has clicked for them, and once that happens it actually becomes difficult to remember why things are hard.
The secret is, that's basically everything in this hobby/field. I've spent months trying to understand things that are now trivial to me.
The best thing I can say is Google, talk to friends, play around with them--not just 'this container' but make your own user (or many users), try and do things, and/remove permissions until it changes. Make predictions as you do this and see ahat you can understand and what's still confusing you. Others have recommended chatGPT, and that's fine too as a source to hopefully give you insight--much like a random blog explaining permissions.
Best of luck, the only thing I can say is don't give up for good but definitely don't worry about giving up for the weekend to give yourself a break! You'll get there and one day it'll be easy.