I used to hear Y2 read, the very best 6-7 year olds put a bit of expression in, most don't. At least they don't to a random mum, they might with encouragement at home.
Generally I found they just wanted to race through as many pages as possible to get higher up the book bands than their friends.
DD2 certainly put loads of expression in her reading, for everyone because the mum who took over hearing Y2 used to write embarrassingly nice things in her book.
DD2 read very well by 5-6 and is a natural actress. Reading with expression came naturally to her as soon as she learnt to spot full stops.
(This did take a while).
Because she read well she would take pages or characters in her bed time stories and I guess DH and I both put bits of expression in when we read. DH because he's done bits of drama, me because I'm dyslexic. If I put in a bit of expression I slow down and don't paraphrase stuff.
She's a bit of an actress and a lot of a show off so she quickly started throwing in expression too.
DH and DD2 spend ages even now she's 12 sharing Garfield, Calvin and Hobs and Asterix books and acting out the parts.
DD1 is more dyslexic than me, she is a total book worm, but didn't learn to read until Y6. I think she still relies on context and her amazing comprehension skills and doesn't decode every word. She almost never reads out load and makes loads of mistakes if she does.
However, she learns songs and drama lesson scripts without trouble and chucks expression in when she performs.
Either way OP it's a talent worth developing because the confidence to express yourself can be very useful both in Drama and Music at school and in life in general.