So we all know that Naruto and Sasuke both received half of the Sage of The Six Paths chakra.What most people are wondering about Naruto's so6p chakra mode and if he still has it.Well I've been thinking and I think he didn't get weaker by possibly losing it.Here's why: When the so6p was nearing his end he split up the Ten Tails' chakra into 9 different parts.They're known as the tailed beasts.Kurama(Nine tails) is about half of the Ten Tails original strength(I can't source it but if somebody could I'd appreciate it).Now,Naruto first started with only half of Kurama's chakra.But post Naruto-Sasuke fight it can be assumed that he received the other half.Now here's my point,Since Kurama is half of the Ten Tails' chakra and Hagoromo is the Ten Tails' jinchuuriki,he basically gave Naruto HALF of the Ten Tails' chakra,allowing him to enter so6p mode.Well after the fight at the valley of the end,Naruto still kept half because he sealed the other half of kurama inside him.During The Last.It's shown he goes into bsm mode.So both halves of kurama's power mixed in with sage mode is around the same strength of his so6p mode.Sorry if that got confusing,This is just coming out as I think
TL;DR:Naruto bsm mode by The Last=so6p mode
TL;DR:Naruto bsm mode by The Last=so6p mode