Is supplicating against disbelievers — such as by saying, "O Allah, abase disbelief and disbelievers, and destroy Your enemies, the enemies of the religion" — considered an aggression in supplication?

Excess in supplication (Du'a) means overstepping the permissible bounds and contradicting the intent of the Lawgiver. This includes asking for what is impermissible to ask for, such as assistance in committing unlawful acts, or asking for something that Allah does not do. Thus, any supplication that contradicts Allah's wisdom or His law, or contains something contrary to what He has informed us, is considered excess. Excess in supplication generally does not apply to invoking curses upon disbelievers, because it aligns with Allah's judgment concerning them. However, invoking a curse upon a specific disbeliever should be done with caution, as one does not know their ultimate fate. The better approach is to supplicate for their guidance.