Not OP, but I very recently switched from bash. Autocomplete with suggestions is a way better exeperience on zsh than bash. The way you can choose between options of the autocomplete/suggest interactively feels way better than bash. I set it up to be case-insensitive, so I can type cd dow and it will become cd Downloads. Gettig autocomplete for both kubectl and its alias k is seamless in zshrc but requires an extra line with a weird dunder function in bashrc.
This is just what I found in a few days of using it. There was no learning curve at all, everything just felt easier.