I need help creating this edge pattern on the jeans hem

Redo with longer srltitch (2x what you have now). Stretch fabric as much as possible as you sew. Use a high tension setting on top thread. Soak the new hem in hot (almost boiling) water and throw in dryer on high for an hour. Lightly sand paper the tops of the ripples.

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You can’t without some sandpaper. That’s caused by shrinkage in the factory during the process of making them. There is no way to actually replicate it in the home without just distressing them by hand.

You've had a few good tips here already by the look but wanted to chime in with fun facts: apparently that pattern is made by the type of sewing machine used (combined with weathering) - they use a specific type of sewing machine that does a chain stitch which uses a single thread and no bobbin (originally used so that if seamstress made a mistake it was very quick to rip out a seam). They inadvertently made this hem detail which became part of the aesthetic therefore are still used today for demins. No other mass produced clothing uses this type of machine as far as I'm aware.

Mine have always gotten the weathered look on their own after so many washings

You can shorten the jeans and keep the original hem. Below are some directions. There might be others out there, too.

https://www.craftsy.com/post/how-to-shorten-jeans/