I have a Canyon Strive 2017 with a race face chainring with the markings d40421 Clinch 30t that I would replace for a sram gx upgrade kit from R2. However the chain ring comes in 2 options with a 3 or 6 mm offset.
Cannot find any indication on the old ring. Which should I use? Does anyone know so a I order the right one? https://r2-bike.com/SRAM-X-SYNC-2-GX-Eagle-Direct-Mount-chain-ring-12-speed-3-mm-Offset-BOOST or https://r2-bike.com/SRAM-X-SYNC-2-GX-Eagle-Direct-Mount-chain-ring-12-speed-6-mm-Offset
According to some specs I quickly pulled up, the width of your hub appears to be 142 mm (confirm this by measuring your hub or the inside faces of your dropouts).
If this is correct, get the non-Boost (6 mm) version. If your hub and frame are actually 148 mm, the 3 mm offset is the "correct" version, but you can usually use a non-Boost for improved chainline. That's what I've done on my last two bikes and it really improves performance in the lowest sprockets.