On the subreddit, the game’s update files are frequently discussed in the context of Yuzu and Ryujinx emulation. When the official patches (1.0.5 adding MotoE, for example) were released, the community quickly looked for NSP versions to update their emulated copies. The general consensus is that the game runs best on high-end PC hardware via emulation, where the resolution and framerate can be scaled up, circumventing the Switch’s native hardware limitations.
Your system firmware is too old for this specific update version. Update your CFW and stock firmware. MotoGP-21-NSP-Update-ROMSLAB.rar