I wonder if the future Star Wars project (Adept) will be partly about the Sith working on getting their old temple setup to interfere with the Jedi by the time of the Clone Wars a few hundred years later.
The timescale there is too short. Like I said, it's
ancient. A thousand years at the very least. Indeed it's so far down that it may predate *all* Jedi presence at that location. We know the Coruscant temple wasn't the first, and that there were other prominent ones in antiquity even after Ahch-to; Ossus, Tython, Ilum, Jedha, etc.
Maybe at the time of the Sith schism the Jedi didn't even have a presence on Coruscant at all and it was some other now extinct force using/worshiping group that occupied it. Then when the Sith conquered the planet, they recognised the power of the place (indeed, it may have been the whole point of the invasion in the first place), wiped out the monks or priests or whoever was there, and built their own place of power over it. Eventually Jedi and/or the Old Republic forces took back the planet. Cleansing the site and building a temple to watch over it (like the one that showed up in 'Resistance'.) At some point later, perhaps centuries later when Ossus had fallen and Tython was lost to them, the bulk of the order moved to Coruscant, expanding the temple as the massive city levels rose around it. Then came Darth Bane's empire and the fall of the Old Republic, and the temple was sacked (bye bye Darksaber), which is probably where knowledge of the shrine was lost with the burning of library (there's always a burning library when these thing happen.) Eventually Bane is defeated, Coruscant is again liberated, the ruined Jedi Temple rebuilt and the Jedi go on blissfully unaware they've set up shop right over a time bomb.
And it's not the Sith actively setting it up to "do" anything, it just is. The Jedi knew it was down there once, but they thought it had been nullified and capped. So they just built over it, and over time (possibly thousands of years), forgot about it. The Sith are certainly aware of it (though when is an open question), have certainly taken full advantage of it, and may have even given it a nudge or two over the generations, but there's no way to think this is all part of some elaborate millennia long plot.