your data

In[]:=
data=Association["Workflow"->Association["modeling"->Association["imagining"->imagining,"binarizing"->Association["asserting"->asserting,"infering"->infering],"quantifying"->quantifying],"simulating"->Association["decomposing"->decomposing,"transforming"->transforming],"governing"->Association["testing"->testing,"observing"->observing,"controlling"->controlling,"solving"->solving]]]
Out[]=
Workflowmodelingimaginingimagining,binarizingassertingasserting,inferinginfering,quantifyingquantifying,simulatingdecomposingdecomposing,transformingtransforming,governingtestingtesting,observingobserving,controllingcontrolling,solvingsolving

layout functions

ToRow and ToGrid are called out as their own functions so that you have some place to put common behavior. For example, you could add styling to the label cells and value cells. I’ve left Leaf undefined so that it shows up in the output to better illustrate how this bottoms out. I know you said you already tried Grid, and so I’m not saying this is the final answer. I’m just demonstrating one way this might be done.
In[]:=
ToRow[label_,value_]:={label,LayoutElement[value]}
In[]:=
ToGrid[g_]:=Grid[g,FrameAll,AlignmentLeft]
In[]:=
LayoutElement[a_Association]:=ToGrid[KeyValueMap[ToRow,a]]
In[]:=
LayoutElement[elem_]:=Leaf[elem]

examples applied to your data

In[]:=
LayoutElement["imagining"imagining,"binarizing""asserting"asserting,"infering"infering,"quantifying"quantifying]
Out[]=
imagining
Leaf[imagining]
binarizing
asserting
Leaf[asserting]
infering
Leaf[infering]
quantifying
Leaf[quantifying]
In[]:=
LayoutElement[data]
Out[]=
Workflow
modeling
imagining
Leaf[imagining]
binarizing
asserting
Leaf[asserting]
infering
Leaf[infering]
quantifying
Leaf[quantifying]
simulating
decomposing
Leaf[decomposing]
transforming
Leaf[transforming]
governing
testing
Leaf[testing]
observing
Leaf[observing]
controlling
Leaf[controlling]
solving
Leaf[solving]