Unsure about best string/wire to use

Hi all, I tried doing research on this but ended up getting more confused with all the options available. As my first beading project I’m making a simple seed bead necklace (w/ 2mm gemstone beads). I’d like it to be an everyday necklace and as strong tarnish resistant as possible. Thus I’m planning to use gold-filled clasps and crimp beads. However, I’m not sure what string or wire to use. It seems that gold filled wire maybe wouldn’t be durable long term, but maybe that isn’t the case? Or should I opt for some sort of plastic string? I don’t want it to be stretchy, though, so not sure which string to use. Any suggestions would be great as I’m not sure where to start. Thank you! (Will cross post in r/ jewelrymaking)