Steering is very stiff to the left - 2004 Kia Sedona

What year is this Focus? First you need to work out what the "Clonk" is. Is this clonk only as you turn or does happen when you hit pot holes? The most common reason for a steering/suspension noise is one of the joints on the system. Get the bottom ball joint, the track rod ends and the drop links looked at.
If your car is before 2011 check the fluid level in the power steering. After 2011 they changed to electric power steering. Sometime the stiffness is that easy to fix. If you need to top it up only fill to the MAX line. After topping it up, With the engine running, turn the steering all the way to the left then all the way to the right and repeat it 3 or 4 times. This bleeds the system.
If the joints are all OK you need to look at the actual steering rack.

stiff steering could be slipping belt for the power steering. while stationary, turn wheels to left and have a look back of wheel see if anything catching, only way.

I need to know the year please.

Check the drive belt to the power steering pump and the level of fluid in the power steering reservoir.

Rack may be contaminated or coming apart inside.

You do not have the proper test equipment, repair manuals and training required to test the electric steering, any suggestion would require you buy a complete steering gear, a very expensive part that may or may not fix the problem, your money would be better spent at the dealer.

Check your serpintine belt for cracks, & dryness. Also if wet the steering will not operate easily neither

Could be an air lock in the system.Leave the engine running with the fluid cap off and turn the steering from lock to lock several times .

the rack has valves in it and the left sounds like it is failing

Check the whole assembly of the left connected to steering... example the left rocker arm and others...