Are we entering a new Ice Age according to Milankovitch cycles?
It thus seems reasonable to say we are entering another Ice Age according to Milankovitch cycles.

Some of the Milankovitch conditions would appear to make the Earth ripe for a new glacial epoch starting now, or perhaps a few hundred years ago. In particular, aphelion occurs in early July, and obliquity is low. Both of these make for mild northern hemisphere summers, a key condition needed for snowfall from the previous seasons to linger into fall.
But one other key Milankovitch condition needed to make snowfall linger, orbital eccentricity, argues against a new glacial epoch starting now. The low (and decreasing) eccentricity makes the current dip in summertime insolation at high northern latitudes too small of a dip to trigger the onset of an glacial epoch. Look at the graph you posted in your question. Glacial epochs start when summertime insolation at high northern latitudes drops to very low values. The current local minimum is not low enough to enable widespread accumulation of snow and ice over the summer.

Some of you may cite the current anthropogenic climate change as a rebuttal, but for the question's sake, just ignore it.

Even without anthropogenic help, the current interglacial is likely to last for 50,000 years [Berger and Loutre]. With anthropogenic help, the current interglacial may even last indefinitely [Steffen].

Throughout geological history, Earth has seen far lengthier and more widespread glacials than interglacials. Indeed, interglacials are just short blips in the geological history.

That is true only for last 2.58 million years, possibly the last 34 million years. The Earth has been ice-free for most of the last 550 million years. Ice ages (periods during which ice can form, intermittently, are just short blips.

References:
Berger, André, and Marie-France Loutre. "An exceptionally long interglacial ahead?." Science 297.5585 (2002): 1287-1288.


Steffen, Will, et al. "Trajectories of the Earth System in the Anthropocene." Proceedings of the National Academy of Sciences 115.33 (2018): 8252-8259.