I sew, and I wouldn’t even bother looking for linen in your local fabric stores. Most everything is going to be mixed with rayon and too narrow for sheets. That’s especially true if your local fabric store is Joann. I can recommend some online retailers, but my usual go-to in the past has been Ukrainian linen, and… uh, you know.

For your current sheets, it will take time for them to soften, but if you wash them on hot and tumble dry them, they’ll soften faster. There are multiple types of linen, and there’s a variety called softened linen where it’s been basically been beaten to soften the linen fibers and simulate wear. Linen that hasn’t been softened just hasn’t gone through that process and will be scratchier.