Lexan is pretty much like Acrylic.
I did a Project last week with 3/4" acrylic.
I use the Bosch 85611M 1/4 In. Solid Carbide Double Flute Acrylic Router Bit
https://smile.amazon.com/Bosch-85611M-Carbide-Double-Acrylic/dp/B000GYE1LE/ref=pd_rhf_ee_s_rp_0_2?_encoding=UTF8&pd_rd_i=B000GYE1LE&pd_rd_r=06D8CYJJN6MTTEFKMMFE&pd_rd_w=EaFMg&pd_rd_wg=2GaG3&pf_rd_i=desktop-rhf&pf_rd_m=ATVPDKIKX0DER&pf_rd_p=9d09a1d9-b780-4db3-9f0c-877cce080ab5&pf_rd_r=06D8CYJJN6MTTEFKMMFE&pf_rd_s=desktop-rhf&pf_rd_t=40701&psc=1&refRID=06D8CYJJN6MTTEFKMMFE
I had to carve 3/8" of the acrylic I did 2 passes at 0.1875
After cut the first piece I realize I could bump the feed rate from 20 to 30.
For the Router…Lower speed is best. I played with the router speed from 10 to 23K and 12K I had the best results
Here is the link for the project if you wanna check it out.
hope this help
Thank you!