Incompatibilities. If commands are used to apply both Silk Touch and Fortune to an item, the Silk Touch enchantment takes precedence over the Fortune enchantment for blocks affected by both enchantments. Silk touch is also [JEonly] technically incompatible with the Looting and Luck of the Sea enchantments.
Is fortune or silk touch better?
Compared to Silk Touch, what Fortune does is that it gives players the ability to mine and dig tools that help in increasing the chance of getting a specific or rarer item to drop. The drawback of using Fortune is that you won't be getting any experience points while digging or mining.
Does Fortune affect Silk Touch work together?
In Minecraft base, fortune and silk touch can't be enchanted together.