One can create a file named .bash_aliases in their home directory to create aliases for that user.
Is there a way to create a .bash_aliases that is system wide for all users? I know one can add aliases in the /etc/bash.bashrc file but this is not ideal.
And is there a way to achieve this with other shells such as zsh and fish?
You should put the aliases in /etc/profile or create a file in /etc/profile.d/ for them. Most modern shells will source /etc/profile which in turn sources the files in /etc/profile.d/, so that’s the best spot for things like aliases for all users. See the Arch Wiki page Command-line shell, specifically sections 4 and 5.
I put a myaliases.sh file in /etc/profile.d/ with all of my aliases and they do not show up in the terminal even after I rebooted my computer.