Apple has defaulted macOS to using the zsh shell since macOS Catalina. For many, the switch (if they weren't already using zsh) was as simple as running chsh -s /bin/zsh and everything would appear to be working just fine.
On brand new Macs however, both the .zprofile and .zshrc dotfiles of new users are not automatically populated in $HOME. Even upon creating a ~/.zshrc file, it may seem as if the file is not sourced/loaded upon starting a new terminal session.
The workaround for this is to create a ~/.zprofile file with the following contents:
[[ -f ~/.zshrc ]] && source ~/.zshrc
This will result in a much cleaner shell, loading /etc/zprofile, /etc/zshrc, and your local configuration without having to resolve to hacks with ugly clear flashes such as adding a start-up command like the following:
# I was misguided by terrible tutorials on the webbernet 😡, do not do this!
zsh; clear