I’m guessing it has nothing to do with the strings but with your technique.
If you slide your fingers over the strings it is normal to hear a little bit of that squeaky sound,
but if it is too much; then it must be your technique.
Just slow down a bit and conscientiously play your guitar making sure that you don’t “rub” the strings with your fingers.
Also, try silencing the strings with a combination of
Fretting hand muting, and picking hand muting. (palm muting)
Bottom line, squeaky noises (in moderation) are not too bad, because it lets the listener hear that it is a human playing the guitar and not a programmed computer. But when overdone, it can be annoying.
Good luck. :)
Someday I`ll play like in my dreams.equator's Music Page..