Hey there,
I was having a similar issue being unable to delete the X11 folder in my trash because it "Can't be modified or deleted because it's required by macOS"
I was able to get around this and delete the folder by doing the following, keep in mind it'll require to turn your computer off so you might want to write down these instructions ahead of time.
- Place the alias folder into the trash
- Restart your computer in Recovery Mode (by holding CMD-R as it turns on)
- You'll see a page that says 'Examining Volumes', be patient as it can take a couple of minutes to complete this process.
- Once it does it's thing, you should see the users on your computer show up. Select your user, hit next and enter your password.
- It'll show a page with 'macOS utilities' options in the middle of the screen, ignore these and click on "Utilities" on the menu bar at the top of the screen
- Select terminal, this'll open a terminal window on your screen.
- Enter the following code and press enter: csrutil disable
- It should come up with a message saying Successfully enabled System Integrity Protection, at this point you can now restart your computer normally.
- Open your bin and empty it, you should now get no error message preventing you from doing so. Congratulations, problem solved!
- Very important, once the bin has been emptied, follow the earlier instructions to restart your computer in Recovery Mode (CMD-R), open the terminal window again and enter: csrutil enable
- It'll come up with the success message again once you press enter, you can now restart the computer again normally.
Hope this helps! It's important to re-enable the System Integrity Protection once you delete the alias so you don't accidentally delete genuinely integral files in the future.