The Templar Lab waypoint does no longer exist. Instead, you need to defeat Sirus, Awakener of Worlds and tag the waypoint in the new town, Karui Shores.
Waypoint #91 is the Karui Shores.
However, there appears to be a bug where the achievement will not trigger in town. You will need to tag a waypoint outside of town (and not in a hideout) to get the achievement, after unlocking the Karui Shores. This will be fixed.
I’ve managed to unlock it today, but it was only after I’ve defeated Sirius for the first time (Tier 8, but I think that it is not relevant) and got to the Karui Shores town in epilogue (there is additional waypoint). It did not unlock immediately – I’ve tried to find the masters in the Quarry area in Act 9, and after creating one or two new instances the achievement unlocked. I also had all of the other waypoints unlocked before. Also a side note – I’ve done Quarry for a lot of times before defeating Sirius and it did not trigger the achievement, only after he was defeated.
Sirus, Awakener of Worlds is the main antagonist of the Conquerors of the Atlas expansion. He acts as the final boss of the Atlas of Worlds, and the leader of the other conquerors: Al-Hezmin, the Hunter, Baran, the Crusader, Drox, the Warlord and Veritania, the Redeemer.