Why is the phrase “ve celle senâüke” not recited when reading Sübhâneke in prayers?

The phrase “ve celle senâüke” does not appear in the mutawatir or well-known hadiths regarding the “Sübhâneke” invocation recited at the beginning of prayer. (Ebû Dâvûd, Salât, 122 [775-776]; Tirmizî, Salât, 179 [242-243]) Therefore, except for the funeral prayer, a person performing prayer does not recite this phrase. (Merğînânî, el-Hidâye, 1/49)

Since the funeral prayer is a supplication for the deceased, it is permissible to include other supplications, and the phrase “ve celle senâuke,” meaning “O Allah, Your glory is exalted,” may also be added to the “Sübhâneke” invocation. (Tahtâvî, Hâşiye, 584; Mehmet Zihnî, Nîmet-i İslâm, 427) This is because this phrase is found in some narrations regarding invocations and supplications made outside of prayer.

Source: T.C. Diyanet İşleri Başkanlığı, Din İşleri Yüksek Kurulu