Color blending mode on CMYK

Did they also send you their printers color profile? otherwise the prints won’t be accurate anyway.

Here’s an interesting topic about it

And there’s also a cool feature in Krita, you can have your color selector in CMYK space while your image is that n RGB. That makes correcting colors in soft proofing easier for me, because I can pick close colors from the start. But it won’t prevent out of gammut colors from happening when mixing on the canvas, though.