I've used 5 SDRAM devices with 5 separate memory controllers on EP3C55. One SDRAM for Nios II/f and another four for 7 compressed video data streams over custom made DMA.
MAX10 is faster generation than Cyclone III, so you can use every IO to interface SDRAM even at 100MHz.
However, pay very careful attention to SDRAM examples from, for example, old development kits. You will see that the PLL setup has two output clocks: one for SDRAM controller internally and another for SDRAM device itself. It will have about -3ns clock phase.
I gave you a hint and you can try to understand why
In general, you should also use some primitives for clock output and understand how to write constraints file initially, then follow TimeQuest report.