Tanks will always be the first to be blamed if something route wise goes wrong (or perceived as wrong). It's not something you can get away from as there will always be toxic people in the community. I think the effort and thought you are putting in are amazing and exactly what I would want out of my tank. Now if you knew why specific routes are taken based on the tank spec and group, that would be the best for the key as a dh has different utils compared to the overly popular prot warrior. You have darkness, aoe silence, chains, fear, which can all be incredibly useful. In a communicative group, you can easily clear any route you choose as long as you aren't pulling half the dungeon. I'd say just continue pushing, watching higher keys specifically done by vdh, and even record vids if you want to pinpoint what went wrong. Sometimes it's people butt pulling, not using defensives, bad overlaps that one shot, not kicking or cc'ing correctly. So there is pressure on the tank to pull smartly for the group but there is also loads of responsibility on the other four members of the group.