This is a particularly painful issue for me, I have multiple posts about is as well (like this example).
I have seen older versions of the doc suggest that we can do
ds_plot = ds.TT.hvplot.quadmesh( ... )
ds_plot_widgets = ds_plot.widgets()
...
template.sidebar.append(app.ds_plot_widgets)
The point is the killer app that still eludes me is to allow for the user to dynamically define a dataset which then setps up a map with multiple holoviews.streams that all produce different DynamicMap objects and occupies as much of the template.main as possible and allows for widgets to update properties such as alpha, cmap, tiles etc.