Is it permissible to say "Al-Salat wal-Salam ala nabiyyina Muhammad (Prayer and peace be upon our Prophet Muhammad)" instead of the Abrahamic Prayer (Al-Salat al-Ibrahimiyyah) due to the occasional difficulty in pronouncing "salli (O Allah, bless)" during prayer?

"The ruling on supplicating for the Prophet, peace and blessings be upon him, during prayer is a matter of scholarly disagreement regarding its obligation. According to the view that it is obligatory, it can be fulfilled by any wording that conveys the meaning, and it does not require a specific phrasing. Al-Khatib Al-Shirbini said: 'This particular wording is not fixed, even though the author's apparent statement suggests specifying 'Muhammad,' and Qadi Husayn explicitly affirmed this. So, if one says: 'May Allah’s blessings be upon Muhammad,' or 'upon His Messenger,' or 'upon the Prophet,' it suffices without adding 'upon him' [the pronoun referring back to the Prophet]. The same applies to 'upon Ahmad,' as was authenticated in 'At-Tahqiq' and 'Al-Adhkar.' It is recommended to strive to use the prescribed wording."