Names are hardest to spell when they come from a language with different phonetic rules. Irish spelling, in particular, preserves its own logic, which is why Siobhan reads as Shi-vawn and Caoimhe as Kee-va. The letters are correct, they just follow Irish orthography rather than English.
What you are signing up for
A child with a hard-to-spell name will spend their life gently correcting strangers. Many parents consider this a small price for a name with real cultural weight. Others decide a more easily-spelled variant is the better call. There is no wrong answer, but it is worth deciding consciously.
Anglicised versus authentic
Saoirse and Sorsha, Niamh and Neve, Siobhan and Shivaun. In each pair, the authentic spelling carries cultural depth, the anglicised version carries ease. Some parents choose one for the birth certificate and the other as a nickname. Both can be lovely.