Genesis Bikes - No barrel adjuster - no problem! Inline cable adjusters work but they're a little fiddly and mean splitting a cable outer to fit (addidng a bit flex to the
Get your gears shifting sweetly: How to tune a rear derailleur | road.cc
Rear Derailleur Adjustment | Park Tool
Rear Derailleur Adjustment | Park Tool
Quick Tip: Using the Rear Derailleur Barrel Adjuster - Road Bike Rider Cycling Site
Ultegra R8000 Rear Derailleur Barrel Adjuster Doesn't Work, and Housing Seems Too Short? (details in comments) : r/bikewrench
Changing rear derailleur, barrel adjuster doesn't fit. More in comments. : r/bikewrench
How to adjust your rear derailleur in 5 easy steps