For those who believe in open-source science or need a tool that allows saving projects legally without a license, several excellent projects have emerged in recent years.
Students who cannot install new software (Chromebooks/Restricted PCs). Veusz is a free scientific plotting package. It is not dedicated XPS software, but you can build a peak fitting model inside it using multiple Gaussian functions. It requires you to manually set the peak positions and FWHM constraints. Xps Peak Fit Software Free Download