It appears to me that the brightness of Eta has increased a little since last year. As a northerner, I arrived in Oz last Friday night and I pointed my binos to the star tonight and it was considerably brighter than the three surrounding stars forming a triangle s, p and u Carinae. Last time I saw it (Mar 2019) it appeared fainter.
Wikipedia has a lot of details: https://en.wikipedia.org/wiki/Eta_Carinae
As to differences in spectra, resolution and scale are too different to directly compare them. Also, IR part is very dependent on local (atmospheric) conditions..