In terms of sheer power, Six Paths Sage Mode was Naruto at his most powerful before Boruto. As this CBR article noted, one of Six Paths Sage Mode's signature techniques was the Truth-Seeking Balls. With this ability, Naruto had an energy force he could manipulate into different shapes such as a staff and could use to completely destroy whole areas. The Truth-Seeking Balls could also effectively take out reanimated enemies, which was definitely needed during the Fourth Shinobi World War.
If Naruto's offensive capabilities in this mode aren't impressive enough, then his healing abilities should do the trick and show his clear advantage over his rival. Six Paths Sage Mode gives Naruto the ability to instantly heal organs and rekindle the life force of someone near death. For example, with Guy near death in Chapter #672, Naruto is able to bring him back from the brink. In Chapter #675, he's able to fully restore Kakashi's left eye.
Naruto's abilities are already greatly enhanced in Six Paths Sage Mode, and in terms of power alone, it definitely puts him on par with Sasuke. However, having the ability to heal organs and completely revive someone near death gives the Konoha Hero clear advantages over his greatest rival.
