

I am not aware of any guides, but I know that in order to get the terminal to look like Manjaro’s, you will need to install the zsh shell with the powerlevel10k theme and zsh-syntax-highlighting. I believe they also use either zsh-autocomplete or zsh-autosuggestions.
At least, this was how it was configured back when I used Manjaro several years ago.
In terms of being “safe,” if you mean in terms of data collection/privacy, just because big companies have an interest in Linux, that does not mean your Linux Mint install is sending telemetry back to those big companies with your personal data.
Big companies have an interest in Linux because Linux is the backbone of server infrastructure all over the world. They contribute to the code, but the code is open source, so the community could see if they were putting some kind of telemetry into open source projects, or the community could simply fork the code if a big company tried to do some other objectionable thing.