Ubisoft knows that Origins needs a sequel but will ignore it for anything else

Maybe because they know it actually doesn’t need a sequel since Odyssey is its sequel.

Odyssey is a prequel and not a sequel at all just the next big rpg

Also Odyssey got no sequel either no the Assassin's Creed Vr doesn't count

Of course Assassins Creed VR isnt Odyssey's sequel don’t be silly, Valhalla is. The only prequels done in the series are transmedia, there hasn’t been a video game prequel yet.

Every Assassin's Creed game is a sequel to Assassin's Creed Odyssey

Earlier you said Odyssey didn't get a sequel; now you are saying every game is a sequel to it? Not making much sense I'm afraid. And anyways false, the earlier games don't follow up the same storyline from Odyssey (obviously because they were written prior) only Valhalla does, arguably Mirage as well.

Historical obviously it's the first.

the modern day no not the most recent

A actual sequel to Assassin's Creed Odyssey like a Odyssey 2 could happen with Kassandra In future

You must be confusing this with some other series where they order things by the flashbacks

There could be a game set around Leonius, the Roman Assassin that killed Caligula. Maybe one that assassinates a tyrant like Nero or Commodus.

The Civil War game should have a protagonist, either Union or Confederate, maybe have a choice between the two and possibly even different genders. The protagonist would try to help their side win the war and possibly sabotage the other side. They could either be a soldier or some wealthy businessman/socialite. The Ottoman Empire protagonist would be a member of nobility or maybe even royalty protecting their land from invaders. The protagonist in the British Raj game would also be a member of the local nobility defending their land from the British and trying to free their land from their influence.

Maybe a game set during the English Civil War. You could either play as a Templar or an Assassin. You would help the Cavaliers as the Templar and the Roundheads as an Assassin. It could also be a prequel to Black Flag, with the Assassin being a Kenway.