If MS have the right to buy Ips historically associated with their hardware I would go for Jade Empire or Deadrising (considering a perfect sequel and not another in the same downward slope that made Capcom kill the series)

if not: Sudeki (considering a perfect sequel this would cover a genre sorely missed in the Xbox Line up)

Bethesda Softworks : Arx Fatalis

Quantum Break 2
Brütal Legend 2
Fallout New Vegas sequel which could be something like New New York.

XGS: Lost Odyssey
Bethesda: Hi-Fi Rush 2 (I want to say like New Vegas II, but didn't play the first one...)

Motocross Madness 3

Halo, Forza Horizon, Starfield, Elder Scrolls, Fallout, and Doom are each IP's capable of big sales numbers for Xbox in a world without Gamepass. Xbox just isn't focused on sales anymore, it's all about the player count for them now. 

Xbox Game Studios- Lost Odyssey 2

Zenimax- A new Obsidian developed AAA Fallout side game

Viva Pinata I'd likely play more but Killer Instinct would be more hype to me, I'm not big into fighters but Killer Instinct has the noob mode, they could add a proper story mode, they could do some awesome character crossovers with all the IPs they have now and the OST is God-tier. Viva Pinata is very relaxing, I loved it and it's one of Rare's best titles Imho, both of these titles would fill a missing gap in Xbox's line-up.

Now I'm thinking about Prey 2 as well, Lol. I enjoyed Wolfenstein and Prey a lot, Prey would be awesome and a nice W for Arkane Austin. Wolfenstein is awesome but at this point, I just want closure, I really don't want to wait for Indiana Jones to finish up first before getting closure, Wolfenstein III can come out which will be awesome and then they can move onto something else (I.E. Indiana Jones).

Dishonoured 3.

Really, only being able to fund just 1 from each is pretty tough as there are so many from each that I want to see.

XGS

• Lost Odyssey 2
• Killer Instinct 4
• ReCore 2
• Quantum Break 2
• New Ryse from Crytek with a new historical time period and new characters
• Jade Empire 2 with Bioware/EA

Zenimax

• Fallout New Vegas 2 (though not really New Vegas 2, I want Obsidian to make a new Fallout side game set in a new city, I believe Obsidian expressed interest in doing Fallout New Orleans at one point)
• Wolfenstein 3
• Dishonored 3 (with a new time period and new playable characters since Arkane said that the Kaldwin saga of Dishonored was finished by Death of the Outsider)

• 512GB - $89.99 was $140
• 1TB - $149.99 was $220
• 2TB - $279.99 was $400