I don't think they can reverse 4+ years of R&D in 12 months. Plans do change, but what's more likely to happen is a messaging shift and not a technological/product design shift.
For example, the new CEO might recognize that the "This Is An Xbox" messaging needs to include PlayStation, so she might mandate that any and all future TIAX advertising must include PlayStation.
Remember: each and every single detail around the next Xbox has to be finalized well before it launches. If they're still targeting 2027, then they have zero chance of undoing whatever Spencer's gameplan was for the Nextbox.