Help - How to enter Mechagon Workshop?

First - I’m a returning player after many many years away from the game. I did not play BFA previously, and have ZERO experience with this dungeon.

How to do enter the Operation : Mechagon - Workshop portion of the instance to find and kill King Mechagon?

I’m attempting to unlock the Mechagnome Race. To do so, I need to kill King Mechagon. To do that, I apparently need to enter a “wing” of the Operation : Mechagon dungeon. After much research and lots of searching through guides and videos, I found that most people just speak to an NPC at the inside of the dungeon instance - Jamie Gearknock, who apparently used to transport people straight to the Workshop Wing.

Well… Jamie has zero dialogue available for me. The door to the workshop is sealed shut when I go there in the instance.

Unfortunately, I did not know that leveling past 50 would block access to non-Shadowands dungeons from the dungeon / group finder. So that route is not an option to me.

Any suggestions / advice is welcome. I’d love to unlock this race for a new look as I return to the game.

I could be wrong here as it’s been a while since I’ve done those, other than M+… but… it used to be just one big 8-boss dungeon. For 8.3, they split into two dungeons… JY and WS. If you’re not seeing them in your dungeon finder as separate dungeons, you may just have to run the entire 8-boss run again. Not sure if it reverted back to the pre-8.3 setup or not.

You have enter the dungeon from rustbolt resistance base.
Kill first four bosses. then after you kill aerial boss the door will be open to enter inside mechagon for the last four bosses.