This regime applies only to ULM aeroplanes of "Category A" as defined in Article 1(2) of Royal Decree 765/2022 of 20 September, which do not have novel or unusual design features, meaning those not covered by certification specifications or industry standards previously recognised through acceptable means of compliance by the competent body of EASA, and whose empty mass (excluding the ballistic parachute) does not exceed 120 kg and which are single-seater aeroplanes.

No, AESA will not reply or send you an acknowledgement of receipt of your declaration.
However, the owner or the person responsible for the maintenance and preservation of airworthiness must keep the proof of notification as evidence that the notification has been made.