Focus type says how the lens is allowed to move relative to the sensor. Fixed focus is glued or threaded and locked. Adjustable M12 is a screw you turn on the line. Active or liquid or VCM autofocus is a motor. None of these is a quality grade. They are answers to whether the working distance will stay still.
In one sentence. If the subject sits at a known distance, lock the focus. If it does not, you need travel, and travel has a cost.
Fixed versus set-once
"FF" on a module often means the factory set it. The glass may still have been an adjustable thread at incoming inspection. What you care about is whether the customer can undo it, and whether temperature will undo it for them. Glue, thread locker, and a holder that does not creep are part of the lens even if they are not on the glass drawing.
When you need motion
A handheld tool, a visitor at a door, a robot that looks from 0.3 m to 3 m. Then you buy AF or a liquid lens and you accept power, hysteresis, and a firmware story. Do not buy AF for a fixed tunnel and call it future-proof. You bought a motor that will hunt.
How to filter
Camemaker lenses expose Focus Type. Use it after image circle and EFL. Then look at TTL: an AF unit is often taller. If the page says fixed, ask at which distance. A lens fixed at 60 cm is not a lens for a 10 cm barcode.