As a German citizen, you are obliged to have an identity card from the age of 16. If you subsequently find an identity card that has been reported as lost, you must report this.
Only when you have officially reported your identity card as "found" will a corresponding entry with the police be deleted. After that, you can continue to use your recovered ID card in Germany without restriction until the end of its validity.
If you find your ID card again, you can also have the blocked online ID function unlocked again. This is only possible in person at your Citizens' Office. The Bürgeramt then arranges for the unlocking and, if necessary, informs the police that the identity card has been recovered.
Please note: Germany cannot influence whether and how other states set up their national police information systems or whether and how often they are updated. Therefore, in individual cases, it may happen that foreign authorities do not delete the material search or do not delete it in time and therefore do not recognize the retrieval of your identity card for use abroad or even confiscate it.
If you want to avoid such possible inconveniences when traveling internationally, it is advisable to apply for a new ID when reporting the loss or theft of the ID.