The first thing you have to know about how to use soul speed is that you will not be able to get this with boots simply using an enchantment chart, but you will have to exchange gold bars with Piglins to obtain pre-enchanted boots or a book with the enchantment respective. These books can also be found in Bastion Remnants chests.
About wearing Soul Speed I boots makes the player move 2.5 percent faster, Soul Speed II makes the player move 15 percent faster, and Soul Speed III makes the player move 27.5 percent faster, remember this is true only while walking on Soul Sand or Soul Soil.
Keep in mind that every time you step on one of these two blocks, there is a 4 percent chance that the boots will lose durability, in addition to damage from falls and blows could end up causing their durability to be reduced significantly. Although the Unbreaking and Mending enchantments can be very useful to avoid wear.
This is everything you need to know about how to use soul speed in Minecraft Nether, we hope that our tips and recommendations have been of the greatest use to you so that you can get a lot out of this potion.