The terminology is definitely confusing because people often use “ROM” as a general term for a game dump, even though there are different formats and sources of game data. If you’re researching the topic, it’s better to start with how Switch software is structured, how cartridge data differs from digitally distributed software, and how emulators handle those files. Searches such as switch roms download can lead to very different types of pages, so I’d pay attention to whether a source is actually explaining the technical side. For preservation and emulation, documentation about the original hardware and legitimate personal backups is a much better starting point.