Tang ruo isn't a reincarnation so he doesn't have Wei in his head and all the seal did was restrict us from the normal Martial path,which doesn't really justify tang ruo being op,he followed the same martial path as us,so he should have had similar cultivation limits.
And the others didn't have Wei guiding them,and even if he did guide them,they never showed feats above their level just the peak of their level.
If there was no karmic seal on the mc,they would just follow the true way of martial arts and then maybe they would be able to fight tang ruo without any of his buffs.
Hence why I said the authors portraying of tang ruo makes no sense