@Salah WG with Cross Guild now relevant to the story, here's a headcanon of mine on how multiple events could be connected together for the series finale
Dragon vs Imu
Sabo vs Akainu
Kidd vs Ryokugyu
Law vs Kizaru
Fujitora taken out by Kizaru/Ryokugyu, like Marco vs King/Queen, regarded as traitor
Ivankov and the 4 Commanders vs Gorosei.
Ivankov the center, the 4 commanders from the 4 seas, interestingly there's 5 Gorosei, some similarity there.
Zoro vs Mihawk
Jinbei vs Crocodile
Grand Fleet vs their crew/shady organizations supporting Cross Guild.
This leads to the destruction of Cross Guild
Sanji vs Vegapunk (?)
Marines Sword vs CP0
Blackbeard Pirates vs Red Hairs runs during all of this. Luffy possibly captured that way keeping him absent temporary in the story for the first time ever, so his crew will free him (rescue).
Blackbeard will use the shadows of the RHP to power up his crew with Moria's df, he will block sunlight allowing them to be in their nightmare modes for however long they want. Might go for more shadows beyond RHP even, he's an opportunist
All these to lead to the finale of SHP vs BBP, the mirror crews facing each other
These do seem like logical match-ups based on Characters we've seen so far, however there are still more Characters to appear and Story is much more complicated than it seems imo
Final Villain is neither Blackbeard nor Imu nor Akainu nor anyone Introduced so far
However he will appear very soon and he will be last to fall against Luffy (He is Strongest Character)
As for Blackbeard, he will be Second Main Villain of Story and will be defeated by All SHs + Red Hair Pirates (Similar to Film Red or Oars Fight)
In other words, Strongest Three Characters EOS will be Final Villain, Blackbeard and Final Form Luffy
But before facing those Two, Zoro's Final Opponent is Mihawk, Sanji +Nami will defeat Imu-Sama (Who is similar to Uta and her Devil), Usopp will defeat Weevil + Bakkin (These are Most important Fights after Main Villains, that's why they are given to East Blue SHs)
As for Grand Line SHs, it's difficult to guess for now. However every single SH regardless of who they fight will also have a Sub-Plot for them where they each solve a Problem or fill an Important Role
As for Admirals, I believe they will be defeated by Leaders of Final Alliance, Shanks defeats Akainu, Luffy defeats Kizaru and Dragon defeats Ryokugyu
As for BB Commanders, I believe SHs gonna defeat them in JoJo Style Fights when they are traveling to the Final Destination
For example, Van Auger can snipe from different Islands, he obviously won't be fought in a small area. Each of Commanders will endanger entire Crew and almost defeat them all alone, but always One SH saves the day
When Van Auger starts sniping them from Miles and Miles away, even Monster Trio can't do anything, so Usopp must take care of him
Catarina Devon will use her DF to trick everyone and cause internal conflict, but Nami will outsmart her and save the day
Laffitte is a Hypnosis and might do some Genjutsu-Like stuff, but Robin will counter him due to having a very Dark Mind
Doc Q is a corrupt Doctor who tricks people similar to Witch from Snow White Story, and he might make entire Crew Sick but Chopper saves the day
And so on ... etc
The idea is that BB Commanders will face entire Crew one at a time almost defeating them all, but one SH always finds the solution
Now I'm left with Fujitora, Aokiji, Lucci, Sabo, SSG, Crocodile, Moria, Smoker, Yamato, Marco, maybe Doflamingo, Hancock, Kid, Law ... etc
I will think more about them