I think if we want a clangd’s include-cleaner as a standalone tool or clang-tidy check (and I agree using clangd interactively for cleanups is painful), we need to extract it out of clangd.
(We’d also really like to use this for cleaning up other codebases).
Proposed it here: [RFC] Lifting "include cleaner" (missing/unused include detection) out of clangd - #2 by sam-mccall