After updating to 1903 my overclocking settings worked just fine, I always Image my system drive before any windows feature upgrades, I take it you never made an Imaged before upgrading? Also have you tried clearing cmos and starting overclocking fro...
My 4790k base temps are around 35c Im using the Noctua DH-15 with push pull fans, I have a Corsair obsidian 750D with 5 fans so moving a good bit of airflow, your temps do seem a tad high could try reseating cooler I use artic silver 5 spreading thin...