I do myself a favor by not doing this, install ohmyzsh and start working. Seeing what other people have done with shell, vim and all sorts of things, I know this is a rabbit hole and I could spend endless time on it. That's why I use ohmyzsh, VSCode and other tools and only tweak settings when necessary. And I can be actually productive even when I get a new machine.
Performance? If you are talking about the startup performance, no it doesn't bother me. Again, nothing is slowly enough to cause noticeable delays in basic typing/editing and the bottleneck is almost never on them. (I regularly work on codebase of hundreds to thousands of files or more.) So I don't spend time worrying about saving a few seconds in total per day when I can use my brain elsewhere.
Performance? If you are talking about the startup performance, no it doesn't bother me. Again, nothing is slowly enough to cause noticeable delays in basic typing/editing and the bottleneck is almost never on them. (I regularly work on codebase of hundreds to thousands of files or more.) So I don't spend time worrying about saving a few seconds in total per day when I can use my brain elsewhere.