What kind of crimping tool do I need for these bullet-style cable connectors?
tl;dr: Get a pair of HS-40J -type crimping pliers.
(This answer partially relies on information in @JACK's and @ThreePhaseEel's answers.)
Here's the kind of plier jaws which should work for you:

this type of jaws, and pliers, is named HS-40J. You'll notice the color-coding - but also the cross-section area, in square millimeters, listed:

0.25-1.0 mm^2 - Green
1-1.5 mm^2 - Red
2.5 mm^2 - Blue
4-6 mm^2 - Yellow

It is customary to have wire connectors obey this color coding, e.g.:

Other jaw sets - even from the long list you posted - may also work, depending on the cross-section area, but sometimes they have weird target shapes.
You will need to figure out the cross-section of your wire - not your connector - and crimp around the wire, accordingly. Specifically, the 4mm connector diameter is not the number you need to use. Please follow the rule: &quot;Measure twice, cut^H^H^Hcrimp once&quot;...
Here's how a full pair of pliers looks, with typical dimension and weight: