For the fan speed controll via BIOS, I ran into the same problem where my SL120s didn’t show up - this was the solution I finally found https://www.reddit.com/r/lianli/comments/k37m9y/sl120_not_recognized_by_bios_try_this
Get yourself a splitter for the 4 pin fan cables. Disconnect one set of fans from the controller. Connect the unplugged set of fans directly to the splitter. Connect the controller to the splitter. Connect the splitter to the motherboard.
Your bios should now see your fans. You can create custom fans curves and dynamically control the speed of the fans.
It may not solve the problems you’re seeing, but it seemed worth sharing.
We’re just air conditioners