What stat does Benediction work off of, again? What about Hallowed Ground?

Stat/skill scaling does. not. work.

I could very likely hit the post character limit digging up every thread that has thoroughly demolished this proposal.

You have to begin every one of these suggestions with the understanding of what the devs are trying to accomplish with the current system. With level sync, as designed, devs have a simple, scalable, effective means to keep all players on relatively even balance.

Unless your idea can achieve that same outcome, it's dead in the water.

You flat out mathematically cannot balance a "stat synced" level 90 full-kit WHM with an equivalent on-level 15-20 WHM in beginner dungeons.

In conclusion, if you don't want to be synced, don't run synced content. If you want rewards from synced content, suck it up, because trying to make the content in any way easier or more palatable means reducing those exact rewards.