Custom Ecto.Type to be used as embedded schema?

Is there a way do define an embedded schema that could be used for embeds_one but still behave as custom Ecto.Type with load, dump, etc. callbacks?

Parameterized types at the time of development were for some time intended to replace embeds, but iirc there either were some blocker or it was to much work to get that change rolled out. So it might be possible, but nothing exists at this time.

I see. Thank you for your prompt response.