Welcome to Android Central forums. I've never heard of the S10 needing any special cable for fast charging. As far as I know for the S10 it's more about the brick than it is the cable. Just a few questions first.
Have you used this brick to fast charge in the past?
When did it stop fast charging?
Have you checked in your settings to see if fast charging is enabled?
S10 I believe takes a 15 watt charging brick, do you have a 15 or 25 watt charging brick?
What prompted you to buy a new charging cable?
I assume that when you plug the cable in it doesn't say fast charging what are your charging times like? You should understand that fast charging only really affects the first 50% of the charging cycle, from 50% on the charging actually slows down as so not to overload the battery. Are you charging from 10% to 50% or 0 to 50%?
You more than likely don't need a new cable, check that your phone is set up to fast charge, check that you have the proper charging brick 15 to 25 watts, and check that you're charging port is clean and clear of debris. Let us know what you find and we'll go from there.
Facebook
Twitter
Instagram