I don't understand why people complain that Nagato only lost because he lacked mobility, he always lacked mobility, his legs were damaged during his battle against Hanzo and Nagato wasn't even in his prime back then, he barely knew how to use the rinnegan so this state can't be used in a debate.
It's not Kabuto's fault either, Nagato couldn't dodge the Totsuka blade because he lacked mobility, even if he had full control over his body he still wouldn't have been able to dodge it.
However, Pain (6POP) could beat Itachi fairly easily, their techniques might be somewhat weaker but Itachi is at disadvantage since he is outnumbered, as we all know Itachi's stamina is very low he won't be able to defeat all 6 Paths, he can't spam amaterasu nor susanoo, Pain's multiple summons alone would would put a strain on Itachi, he will probably be already exhausted and half dead before killing them all and I don't see him sealing all 6 Paths not to mention they have full mobility this time.
It's not Kabuto's fault either, Nagato couldn't dodge the Totsuka blade because he lacked mobility, even if he had full control over his body he still wouldn't have been able to dodge it.
However, Pain (6POP) could beat Itachi fairly easily, their techniques might be somewhat weaker but Itachi is at disadvantage since he is outnumbered, as we all know Itachi's stamina is very low he won't be able to defeat all 6 Paths, he can't spam amaterasu nor susanoo, Pain's multiple summons alone would would put a strain on Itachi, he will probably be already exhausted and half dead before killing them all and I don't see him sealing all 6 Paths not to mention they have full mobility this time.