Make catsup more clingy
The go-to industry standard additive to ketchup to make it "optimally clingy" is xanthan gum. It makes all water-based fluids into shear-thinning non-newtonian fluids, which means they flow just okay out of a bottle, but cling to surfaces well.

If you can't (or don't want to) use that, there's a bunch of easy natural thickeners. Potato or bean puree (blend with a small amount of your ketchup to make it easy to mix in),  gelatin or potato starch (prepare hot with water, pour/mix when lukewarm). Arrowroot.

Also, consider reducing the tomatoes some before preparing the ketchup. Less water since moment one will make it thicker.