Does 100% rye sourdough bread always has sticky crumb (an inside)? How to make it less sticky to knife?

Every time I make a 100% rye sourdough, it sticks to the knife when I cut it even after letting it sit for a day before cutting. Is it normal? I tried to vary hydration ratio a bit, but it still behaves the same way. Is there some "additive" to make it less sticky? Is it a must to add wheat for that?

Sourdough starter I maintain is simple: 2 cups of flour and 2 cups of water.

I dissolve malt syrup, molasses, salt, and spices in a warm .5-1 cup of water. Then I add starter, 4 cups of flour, mix it and transfer right away into loaf pan. AFAIK there is no need to fold 100% rye bread and it raises fast. I bake it at 350F for slightly over an hour. I sometimes use Nu Wave infrared oven (40 min), but the very bottom is not quite crispy.

The final bread looks and tastes good. But that stickiness to knife and rolled "crumbs" are driving me crazy. Is there something I can do to minimize it?

I heard that over-proofed starter can help lower pH and help pentosans keep bread structure and make them absorb less water. I tried making the bread with quite well proofed starter. But it made no difference. Do I have not enough starter for that amount of flour? Shall I move some flour there to prevent pH from raising much?