Any exit command in a shell's respective dotfile, or an interactive control-D will cause the Terminal to issue that [Process complete] message. You then need to quit and relaunch the Terminal as the current shell process is toast. Verify that no shell dotfile has that exit command in it. Perhaps something naive in that .NET Core 8 installation process.
I left my Bash shell dotfiles in place though I am using Zsh in the Terminal. Zsh does not read Bash dotfiles and I use just two — ~/.zshrc and ~/.zshenv. You cannot have both shells unless, in a shell script, you use the appropriate shebang for the opposite shell. Although one can manually enter /bin/bash in the Zsh shell, and it will deceptively give you the Bash prompt, it is still the Zsh shell.
To make the Terminal use Zsh, you simply run the change shell (chsh) command shown to you by the Bash shell and configure a ~/.zshrc file. Do not enter any content in the Terminal > Settings > Profiles > Run Command window, or in General Shells open with: take the default login shell.
Only if you do not have a ~/.zshrc file, run the following HERE script which will write the file with PATH and PS1 prompt settings. Revise as needed.
<<"EOF" > ~/.zshrc
export PATH=".:/usr/local/bin:${PATH}"
PS1="%m: %~ %% "
EOF
You probably know to press return after you copy/paste the HERE script to your Terminal window. Then, if you have the Zsh shell running, issue the following command to set these environment variables in the current session:
source ~/.zshrc
