At wano’s end, Shanks said he didn’t want to meet Luffy because he had to deal with Bartolommeo.
Next time we see Shanks is when he fights Kid at Elbaf. However then we see he beat Bartolommeo 1 month earlier.
This must mean, he first went to Gartel island to fight Barto immediately after wano, then 1 month later beat Kid at Elbaf, which is around where we are right now in the story.
This explains why some characters seem noticeably stronger: Sanji used IJ HM, Kid and Law spammed DP and Ope awakening, Franky might even have haki.
It also has to mean something happened to Drake between Wano and Egghead as there’s no way he’s still wearing bandages from Wano when everyone else is healed.
Lastly, why did Oda have Barto lose 1 month ago? I think it could be that the Barto Club will be involved in Elbaf. See the RHP went to Elbaf after defeating Barto. So if Barto survived and is looking for revenge, he could have followed Shanks to Elbaf.
Perhaps he saved Kid or otherwise united with the Kid pirates once they washed up. Now you got them somewhere on Elbaf possibly allying against Shanks.
Ultimately it was the grand fleet that gave Usopp his title of “God”. If Usopp is to achieve his dream in Elbaf, the grand fleet might be involved. Hajruddin will surely be in Elbaf. Why not Barto as well?
Perhaps we could see Usopp and the GF winning a battle against Yasopp and some RHP allies, with Usopp accomplishing his dream by surpassing Yasopp. If not in outright strength, at least surpassing him as a pirate by leading a powerful crew like the SHGF.