Whether fiber helps or doesn’t entirely depends on the implementation. If it is purpose built for audio it can sound better. If the conversion is with cheap converters incorporated just to have it… like the ones on TVs, then they will not sound good. This is why optical has up until recently been completely dismissed by the audio comunity. There are a few good implementations now.
Ways to make your digital streaming sound better
Having tried a lot of different methods including fiber optic , sonically Conventional
Quality ethernet cable sounds more realistic , first at your modem router combo -get rid of the $5 wall wart it is nothing but added noise . Little green computer sells a decent 8 amp 12 v type for $300, that was much better , better still was the Linear Tube Audio LPS , on your router it states the voltage and most are around 4 amp. These LPS go to 8 amp for $700 on Audiogon . Then you need a respectable Ethernet switch,the best one I have found has a LPS built in as well as a OCxo clock -LHY -SW8 , you need 2 Ethernet cables ,your best one goes to your Streamer ,that’s where it makes the biggest improvement .
with the latest Eversolo DMP -A8; really made a nice improvement just by doing these few things many Audiophiles overlook .your streamer will thank you as well as your ears . Excellent streamer dac -preamp for under $2k .Many Excellent reviews . a mini review to follow