Is changing the wording of Quranic supplications to suit personal prayer, or adding names of glorification to Allah in established invocations (adhkar), considered an innovation (bid‘ah) or a good deed?

It is permissible to change the masculine form to the feminine or the plural to the singular when supplicating, if the intention is to supplicate and not to recite, so that it aligns with the supplicant's situation. However, regarding the supplication after the Athan, the word "al-Atheem" (the Great) has not been mentioned in any of its narrations. Therefore, one should restrict oneself to the wordings found in the authentic Sunnah.