Touchy Sudoku

Hands / Touching hands / Reaching out // Touching me, touching you // This is a Touchy Sudoku, which is a challenge to set and this version of this puzzle is a bit of a challenge to solve.

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!