Directions:

Shift-scroll to change selected mob, right click scan for target mob, that's all there is to it.  All mobs within range will be highlighted and the distance to the nearest one will be displayed.

Same goes for the passive finder except it has a bigger default range.(150)

Range is configurable for both (default:64), but use caution when inputting values above 120 on the mob finder as issues may occur due to rapid spawning/despawning.

Demo

Recipes

Default recipes, feel free to change them with Crafttweaker

Simple mob radar

Simple passive radar

 Open to suggestions, join the Discord