The New Approach to Training Volume Strengtheory
Here is an article I read a few months back, that kind of got me to switch over from continuing to increase the weight of my dumbbells and instead switch up to increasing the number of reps, and trying to increase the number of sets I do per workout. (back in january I was doing 3 sets of 8-12 reps with the heaviest weight I could successfully do that, increasing the weight whenever I could hit 15x3).
I appear to still be gaining muscle mass / hypertrophy in my arms and shoulders, and yes, my muscle endurance has definitely increased.
I still occasionally (maybe once every other week) do exercises with my heavier adjustable dumbbells (up to 90lbs x 2 for dumbbell deadlifts, but for most of my workouts I'm just continuing to use the standard 40lb hex dumbbell just because of the simplicity/ease of keeping it next to my bed)
And yes, I've switched back my diet to a slow cutting/maintenance diet. I am gaining a lot of definition again in my upper chest, although the gut is still there.