The best solution is Gelion software. Write to the authors at Moscow State University, they give a beta version of the program for testing for free (e-mail in the photo):https://www.researchgate.net/publication/349663204_Computer_vision_and_hyperspectral_imagery_in_orchards_and_in_fields_Data_processing_and_analysis_methods

Thanks a lot @Vjacheslav Fisenko. I'm going to try that for sure.

It really depends on what exactly you have in mind. There are several software packages dedicated to spectral data processing, including some free ones. Personally, I prefer using Essential FTIR (https://www.essentialftir.com/). A 30 day free trial is available so you can give it a try. In terms of spectral manipulations here you can find a list of the features included: https://www.essentialftir.com/dataManipulations.html

Thank you. I'll give that a try for sure.