What is the ruling on prayers performed with or without the repetition of the letter "ra," and does the assimilation of "ra" into "lam" in "Rabbi-ghfir li" invalidate the prayer?

We advise the questioner to disregard the many whispers (waswas) and not pay attention to them. The repetition of the letter 'r' (tarkir) is an inherent characteristic of it, and one must be cautious not to exaggerate it. Its repetition should be concealed such that the tip of the tongue vibrates a single, light vibration. The repetition of the 'r' does not invalidate the prayer. Not assimilating the 'r' into the 'l' (idgham) is what the majority of reciters (qurra') hold, but assimilation does not harm the prayer or anything else. Based on this, the questioner's prayer is valid.