This likely the Pro, but I am sure a LOT of people wont accept that likelyhood...I said it all along. Easiest, cheapest, most Nintendo-like Pro path is just to upclock the in place Tegra and change nothing else (plus that's Nintendo's history aka new 3DS).
If it was RAM challenged, aka it had 2GB, I can see them upping RAM, but 4GB RAM is plenty in Switch's price slot in todays market and relative to the performance. Further, RAM often can only be doubled due to bus width constraints (not sure if this applies to Switch SOC) so the next step has to be 8GB, not 5GB or 6GB. And that's too much/expensive/unnecessary.