is somebody using an Ultegra RD-R8000 SS Rear Derailleur with a 11-32 tooth casette? Shimano says it works for up to 30T and ceramicspeed says it works for up to 32T :
Tinkering 101: Shimano 105 Derailleur Hack by Thomas Aceves - Gravel Cyclist: The Gravel Cycling Experience
A guide to rear derailleur cage length: Short, medium or long? | the accidental randonneur
Shimano Ultegra RD-R8000 11spd Rear Derailleur GS Mid Cage - Cassette up to 11-34 [IRDR8000GS] at BikeTiresDirect
Shimano Ultegra R8000 Mechanical Rear Derailleur RD-GS Medium Cage - Black for sale online | eBay