Mod Version: 1.15.2-0.1.2
Forge Version: 31.2.33

I cannot seem to find any way for obtaining straw.

this is not an issue, you have to break grass, grown wheat and grown rice with any type of the knives from this mod. and the advancements hints the recipe

@nrtcb You are right! Don't know how I missed that... 😅 Thank you for your time!