Your 2018 arrow has a .464 spine weighing 12.3 GPI (grains per inch).
If you want a lighter arrow with a very flat trajectory in your spine range, try a 2213 with a .460 spine and it weighs 9.9 GPI (grains per inch). You'd have to experiment with point weight to give you the best optimum performance with this setup.
You won't get the same penetration as with your 2018 due to the larger diameter, but the 2213 will penetrate quite far because you're going to have a much faster and flatter shooting arrow.
Speed (FPS) will compensate for the lighter arrow weight when it comes to penetration and you just might surprise yourself in how far a light arrow can penetrate.
With my 30" draw length, this is why I shoot a 2212 arrow out of my two light poundage recurves which you can see in my signature. Weight isn't the sole factor in penetration, speed also kills when it comes to penetration and this is based on lots of experimentation by me shooting both heavy and light arrows GPP (grains per pound) wise.