I've used a similar setup to finish end grain slices and gotten best results from a 1 3/4” Freud straight bit. Shallow passes with the bit's big cutting area leaves a pretty smooth finish. Minimal sanding (think 15 mins with ROS) to get rid of faint lines.
Also, make sure the wood itself isn't moving at all. That can produce gouges.
Freud 1-3/4 In. Diameter by ¾ In. Double Flute Straight Router Bit with ½" Shank (12-194) https://www.amazon.com/dp/B00004T7CZ/ref=cm_sw_r_cp_apa_rtZHzbA2T2QG2
https://www.amazon.com/dp/B00004T7CZ/ref=cm_sw_r_sms_c_api_ztwGybJKHHQHK
My bits are part of this series:
This low cost bit worked surprisingly well for me:
Magnate 2705 Surface Planing ( Bottom Cleaning ) Router Bit - 1-1/2 https://www.amazon.com/dp/B0006B0QX4/ref=cm_sw_r_sms_c_api_iNwGybJCQKMXB