Touch and Go

I found this constraint in a puzzle by Clover from a few years back. In Touchy Sudoku, every single digit is next to a numeric neighbor, which seems like it could be like Renban, except most digits have two neighbors, and only needs to be next to one. Which seems like it could lead to dominoes, except most digits can be neighbor to two different digits, or to two instance of itself. So it’s not quite like anything else, it’s Touchy Sudoku!

Rules:
Normal Sudoku rules apply.
Digits within cages do not repeat, and sum to the total in the top-left corner of the cage.
Touchy Sudoku: Every digit is adjacent to at least one consecutive digit. That is, every 2 shares an edge with a 1 or 3 or both, and so on.

Estimated difficulty: 1 out of 5