Four Fours: Excellent Construction for a Smooth Sudoku Solve

Today's Video:

We've played a similar 4 x 4 puzzle from Sir Moose. We're back with the same idea but now with a harder puzzle in an 8 x 8 form.

Link to Play:

Four Fours by Sir Moose https://tinyurl.com/SudokuSleuthFourFours

Rules:

The puzzle grid is made up of four 4*4 sudokus. In each sudoku, enter 4 of the digits 1-9 in each row, column, and 2*2 region. Digits cannot repeat in any row or column in the 8*8 sudoku grid.

Digits on an arrow sum to the number on that arrows circle.

Digits on a green German Whisper line must differ by at least 5.

Digits on a blue region sum line have the same sum in each 2*2 box it passes through.