Do you need Google Tag Manager to track conversions?
Definition
Google Tag Manager is a tag container used to fire pixels and events without shipping code. It is useful for ads stacks and many vendors. It is overhead when the job is one product conversion on your own site.
How EventDash implements it
Install one script. Mark the button with data-ed-goal. That is a conversion. Keep GTM if you still run ads pixels or a dozen tags — EventDash does not replace a tag manager for that job.