I'm here to complicate matters. Because in the last 3 months, DC has published the official Arrow-verse comic crossover "Earth-Prime", with five issues devoted to the individual shows' characters being confronted with the new threat, and the sixth issue being the one that brings all the heroes together to fight that new threat (it's Magog, btw). It was also the final official installments of Batwoman and LoT, but we didn't know at the time. Anyway, issue #2 of the mini-series focused on Superman & Lois: It was written by Adam Mallinger, Jai Jamison, and Andrew Wong, who all work on the TV show, and the production team was involved in the development of the comic. The story itself doesn't majorly involve any of the ongoing arcs of the TV show, but the setting is more or less the same. But, it is set on Earth-Prime. And the comic can very much be seen as canon, as other issues like the Stargirl and Flash ones have been used to tease storylines for the upcoming new seasons. So, until there is official word on this one way or the other, my head-canon will be that the Earth-Prime Superman family have had similar parallel events to the characters of the TV show, but slightly different allowing for the differences in the two universes. So, Clark's Earth-Prime Fortress would still be the one seen on Supergirl, not the one seen on S&L.