This mod, Magical Nights, is built off of the version of Magiclysm found in Cataclysm: Bright Nights. As such, some thanks goes to KorGgenT, Aptronym, and LaVeyanFiend for their past work on Magiclysm.
I adopted that version of Magiclysm, becoming its maintainer. I rebalanced Demon Spiders, I rebalanced almost every single spell in the mod, and even added my own content (in the form of my own take on Goblins, some clothing mods (including owlbear fur), and the dragonbone weapons). However, I found myself disagreeing fundamentally with much of KorG's original vision for Magiclysm, particularly in the lore. Thus, Magical Nights was born.
I'm glad you asked! Under KorG's vision, the public has basically always known about magic. However, for whatever reason, the public didn't much care for magic compared to technology. As such, Magical Academies could be found in the cities, but it was rare for anyone in the public to actually use (much) magic.
My approach is instead that magic has long been hidden, ever since the immense persecution that it once suffered. You wouldn't find evidence of pre-cataclysm magic in cities aside from the odd basement or appearance in a book store. Instead, magic is more out in the countryside. Mage towers, Magic Academies, and all sorts of magic are located out in the countryside instead.
Due to the influx of magic following the tearing of the veil between worlds, some magic has made its way into cities and towns. However, it will most likely primarily be magical anomalies and threats. Some intriguing uses and aspects of these urban influxes of the arcane may be discoverable by the player, given some effort.