Yes for some people sinus surgery can change a persons voice.
Some people who have sinus surgery don't report a change in voice while some other people who have had sinus surgery said their voice had changed some.
After sinus surgery your voice may sound more nasally for at least a little while as sometimes your voice will return to normal while other times it may be permanent.
So that is one risk with sinus surgery but most peoples voices do return to normal.
The sinus surgery can change the acoustic characteristics of the vocal tract and produce a significant increase in nasality in the early phase.
However, after proper healing of the nasal cavity, nasality was observed to become similar to the preoperative level.