Opening the book…
Dataverse caches component resources aggressively by version. Import an unchanged version number and the platform will happily keep serving the old bundle while you stare at "unchanged" behavior.
Increment the patch segment of the version attribute in ControlManifest.Input.xml before every build that leaves your machine. Make it a muscle memory, or a pipeline step.
Microsoft Learn — Code components ALM — Versioning and solution packaging guidance