@dankcushions yes! I did the change when I found this new emulator was ported to libretro. At the end I found that the main problem in my lr-genesis-plus-gx performance is the bilinear filter. If I turn it off it's working 58-60 fps with very good sound quality. So as I see it maybe I overloaded my raspberry pi 3B too much, if I'm correct is definitely something to have in mind if you dont have a rpi3B+ or rpi4. SegaCD is working fine too now!
Please do not post a support request without first reading and following the advice in https://retropie.org.uk/forum/topic/3/read-this-first