In the end, the forum thread was right. It was the "best" converter. It converted the file perfectly. But it also converted Kael and Jax from anonymous ghosts into targets, all because they traded the safety of a local, complex tool for the convenience of a cloud-based lie.
Converting NSP (Nintendo Submission Package) files to XCI (Nintendo Switch Cartridge Image) is commonly done to run games on different homebrew-enabled Switch setups or for archival. Online converters are limited due to large file sizes and legal risks; desktop tools are generally more reliable, faster, and safer. Below are the best practical options, pros/cons, and a recommended workflow. nsp to xci converter online best