Baby name wizard has Alexa peaking in the 1990s when combined with various other related names. [1] The specific Alexa variant peaked in 2015 but that's in the context of the related names as a whole declining precipitously, albeit not to pre-80s levels.

I must admit that a reason for the popularity spike doesn't pop to mind but presumably there's some pop culture thing I'm not thinking of.

[1] https://www.babynamewizard.com/voyager#prefix=alexa&sw=both&...