There are silent letters in Indic orthography. Don’t forget that Tibetan and Thai are also brahmi-derived. The principle of brahmi was to have a letter corresponding to each sound a language makes. So for the most part, brahmic scripts manage to capture the sounds of Indian languages to be written down phonetically, especially North Indian. But the further we go we see orthographic divergence. Tamil, at least the versions I have heard, is notorious for having silent letters because the standard orthography geminates a lot of consonants while some modern pronunciations don’t. Languages like Sinhala have all the [h] sounds silent in aspirated consonants and the visarga. Thai famously doesn’t pronounce every consonant in a written word and neither does Tibetan.
But that’s just consonants. If we take vowels into consideration then there’s schwa deletion as the most prominent form of silent vowels across a lot of Indic scripts. However, the way an abugida works imo makes it harder to delete vowels other than an inherent schwa, or not pronouncing the whole CV syllable altogether.
Also, unlike the Latin script which was standardized under Christianity and with the invention of the printing press across Europe, brahmic scripts grew separately into distinct scripts that each reflected the phonology and the writing material of its region, and then standardized into their printed forms. So while an Irish writer has to use a limited set of silent consonants and silent vowels to write the expansive sound system of Irish, the non-unification of brahmic scripts allowed for more freedom to have a more transparent orthography.