So, as some of you unfortunate souls may already know, there are a few discrepancies with the High Gate Ruins dungeon, If you completed the dungeon, killing Vokun, but, sadly, missed either the shout or the dagger (I missed the chest with the dagger because I went straight for the shout and overlooked it completely), you are seemingly unable to ever enter the room again, as the door will always be locked since you cannot kill Vokun again. However, after many hours of ripping my hair out trying to find a new way in (I even tried putting the mask on Vokun and resting for a month so that the dungeon would reset), I had an ingenious epiphany, and it worked!
Here's what you need to do: Acquire any follower in the game. This is the most important step, as your follower will be the key to moving through the obstacle (aka, the closed gate). Proceed to the Dungeon and to the initial room where ansa is located. In the entrance for this room, right as you come through the doorway, look to the left. You will see a fallen pillar that appears to be a possible way to the top platform. You guessed it, a little parkour will be in action. First, however, talk to your follow and ask them to "do something." When the reticle changes, proceed over to the pillar and jump up onto the cylindrical rod of wood protruding from the ground. Once you have done this, jump forward to the pillar. You will not quite make it to the top; however, by moving around and repeatedly pressing jump, you should be able to find just the right spot to jump again and, hopefully, land atop the pillar. This took me quite a few tries, but I seemingly mastered it at this point. Now, once you have made it to the top of the pillar, you will need to look to the right to find a another low hanging wooden rod just below the platform. Jump to this rod and continue to jump up onto the platform in a similar manner as you had to with the fallen pillar. Lastly, go to the closed gate and find the the pull chain on the other side of the gate, on the right wall. Ask your follower to "activate chain." They will run through the dungeon and finally open the gate for you. It will take them a bit of time, but, alas, you will finally receive your long awaited prize.
I will possibly post a follow-up video on youtube of how I achieved this feat. Good luck to anyone who was stuck on this.
Thank you so much for the tip! One question though, approximately how long did you have to wait for your follower to open the door? cause i followed all the right steps (with lydia) and I've been waiting for what seems like at least 30 minutes and she still hasn't popped up on the other side.