The readme file for bash-lsp lists among its features code completion and diagnostics. The mode line for, as well as highlighting within, debug.sh, seems consistent the shown excerpt of config.el. I was expecting a drop down menu with syntax suggestions while typing and that M-x flymake-show-buffer-diagnostics would list the error in the while statement. However, neither is occuring? What eventual minimal additions to the setup should I make, or what commands should I invoke, to obtain the desired behavior?

config.el

(use-package lsp-mode
  :ensure nil
  :hook ((sh-mode) . lsp-deferred) 
  :commands lsp)

debug.sh

#!/usr/bin/env bash
while raed word
do
    echo "$word"
done < <(cat << EOF
foo
bar
EOF
    )

*lsp-performance* (M-x lsp-doctor)

Checking for Native JSON support: OK
Check emacs supports `read-process-output-max': OK
Check `read-process-output-max' default has been changed from 4k: ERROR
Byte compiled against Native JSON (recompile lsp-mode if failing when Native JSON available): OK
`gc-cons-threshold' increased?: ERROR
Using `plist' for deserialized objects? (refer to https://emacs-lsp.github.io/lsp-mode/page/performance/#use-plists-for-deserialization): OPTIONAL
Using emacs 28+ with native compilation?: OK

terminal:

$ emacs --version
GNU Emacs 30.0.50
$ bash-language-server --version
5.4.0
(node:2745450) [DEP0040] DeprecationWarning: The `punycode` module is deprecated. Please use a userland alternative instead.
(Use `node --trace-deprecation ...` to show where the warning was created)
$ uname -a
Linux elitebook 6.9.5-arch1-1 #1 SMP PREEMPT_DYNAMIC Sun, 16 Jun 2024 19:06:37 +0000 x86_64 GNU/Linux

PS: As I understand it, tree-sitter optimizes syntax parsing, so at this exploratory stage I did not delve into it.