There's no one way forward. A lot of things might happen and it will only be decided once a company actually ships a new and viable technology.

Remember what Intel did with the FinFETs. It was the same discussion then (What could the next thing be? III-V, SOI, blabla?). At one point, Intel simply came on stage, surprised us with FinFETs and everybody was like: "I guess it's FinFET, then." The idea of FinFETs is actually from the 90s or so. The sole reason why noone did it before is because noone could actually build them at scale (AFAIK, Intel is still the only company that ships FinFETs).

Keep in mind that manufacturing is very hard. It is very unlikely that there will be more than incremental steps. Just changing the channel material is already quite the task.

Also, don't believe any "This is the next transistor!" stuff. You can find these things a lot but they rarely mean more than some department trying to make a bit of publicity.