Opened PSU and found 25x25x10 and 60x60x10 fans
Going to replace with 40x40x10 and 60x60x15 by EBM-Papst
From 35 en 30dB to 16 and 22 dB with more CFM
unplugged the 25×25 for now (see Snapmaker 2.0 A350 PSU Fan noise Hack)
PSU did not get over 33C while 3D printing the new backplate for 40×40 here:
SNAPMAKER 2.0 POWER SUPPLY 40MM FAN BACK PLATE