Hi! I have these Ultegra 6700 shifters and a Deore 9 speed rear derailleur. They work fine, but they "lose adjustment" pretty easily. I'm thinking about upgrade into this Shimano GRX RD-RX400 (
Shimano Ultegra 6700 Sti Shifters Gear/brake Levers St-6700 6703 Shifter Left 3 Speed Right 10 Speed With Original Inner Cables - Bicycle Derailleur - AliExpress