I would be thrilled to see what this could be but it sounds like a blunder of epic proportions if they did so. Another traditional console would be expensive and or a dud, a handheld maybe would offer a compelling new gateway to the Xbox ecosystem. Some sort of OEM device would be a differentiating factor but again, software support for it would be a pain to meet requirements unless they relaxed them which would basically make it another PC. I just dont see how releasing a new Xbox this year solves their issues related to HW
The best year for a next gen console is 2028 even based on MS's estimates which were leaked from the FTC case. Its not Sony's time table. 2028 is the year when its expected there will be enough technological developments at the appropriate cost both in terms of software and hardware to warrant a new console.
Sony's going to be releasing their titles onto PC between 1-4 years after the playstation release dates, not day and date. And such an Xbox PC console hybrid as you've suggested would come with some serious issues. For example, the only way the game would run without piracy is through Steam or Epic stores but not through the Xbox store since Sony wont be releasing their core titles on Xbox. So consumers would have to be able to install those game store. If anything it may increase the odds of Steam and Epic replacing the Xbox game store. Doesnt make business sense.
I struggle to see how Sony would be forced into being multi platform in such a situation.