It sounds like a valve adjustment is required
There are many items that can make a 'ticking' noise that is tied to the RPM of the vehicle.
Having the sound match RPM's certainly gives a clue that it is associated with the operation of the engine.
Many times a valve adjustment is required. This is a component of a regular maintenance schedule for almost all vehicles.
A valve adjustment ensures that valve clearance between your camshaft and your valve actuator (there are many different types) is correct. As normal wear occurs on the motor the gap between the two increases until enough gap is there for you to begin to hear a ticking noise.
There are certainly other possibilities regarding the sound.
a way to check
You can get a long screwdriver and place the tip on the valve cover of your engine. Then press the handle into your ear and push the tragus of your ear over the canal and you will be able to listen to the inside of the engine. If the valves need to be adjusted you will hear the ticking loud and clear from the valve cover.
IF not, use the technique to listen around the engine bay to see if you can identify the source.
I have a screwdrivers with 18" shafts that are easy to do this with. You could also use a steel or aluminum rod or any other long tool that can transfer the sound through it. It will need to metal.
Hope this is helpful. Good luck.