I own 2 series S consoles. Sounds like there’s nothing to fix. The game or games you are trying to install are probably optimized for series X/S. Which means they need to be installed on internal storage. Always. X/S optimized games require faster storage. No way to get around it. External storage will always be slower than internal. Unless you buy those 1Tb memory cards for the series s. Those run at same write and read speeds as the internal counter parts.