Best plugins for Bash, Zsh complete

I want normal autocomplete for shell scripts in an ordinary file buffer. By normal complete I mean hints for: - keywords - variables - builtin and external command names - options for commands Is there any plugin for this? If there are no plugins for this now - what do you recommend to read along with manual to create such ones? ;)

Have you tried using Bash-lsp (for instance through https://emacs-lsp.github.io/lsp-mode/page/lsp-bash/ )?