Anyone know how to get to this guy hes behind the doorway near Archaeologist Vygun but no clue how to open the rock door if even if you can...

Found him went north west of the Canyon Vugun is found in there you'll find a portal that leads to the new Valencia Part 2 dungeon. Beware of the mobs in there at level 56 with 226 DP the mobs hit me once and took 75% of my HP

He is found in Hystria Dungeon and to enter you must look for "sand swirling" pillar with black portal in the desert. They spawn randmly and it seems to stay 15min. The destination: Aakman or Hystria is in fact random too, weither you go in one or other. To get that NPC i followed on rule inside that dungeon keep heading to full East. I died once and used Elion to stay in there. Mobs are all purple at 57 even 59. They put me at 20% HP with one attack at 192 DP.

Just wave, guys. I spent 100 energy to check and his Interest never drops below 40 and Favour tends to be high too.

Bert is located inside the Hystria Ruins (underground). The entrances to the Hystria Ruins are spawned randomly in the desert. All possible locations are available here: Ancient Teleporter.
I've added two screenshots to the Screenshots tab for the reference. Circled entrance on the first screenshot spawns at 6pm-7pm by in-game time. Second screenshots shows the map of the Hystria Ruins (original is taken from this Reddit thread). If you'll use the circled entrance you'll land on the spot marked with big red arrow. Then just follow the red line on the map to get to Bert.