All four sides- I’ve sprayed them with WD40 but none seem to engage at all. Even when screwed fully both ways to try to free up. The cleats are nearly new- they work on my other SPDs/bike.

The SPDs are quite old though- circa 5yrs+ so maybe the springs have become ‘tired’ over time?!

My current bike have SPDs that are well over 5 years. Im not aware of the springs getting tired.
Are the cleats deffo Shimano ones?
With the spring tension backed right off, can you insert a screwdriver between the pedal body and sprung back plate and move it using the screwdriver as a lever?
Is there something on the shoes that are preventing the cleats engaging?

Will have a waggle. don’t really want to bin them- apart from slight play in the axles they are spot on.

apart from slight play in the axles they are spot on.

and not being able to clip in.

I had this problem with ritchey spd’s. I think it was due to too may rock strikes as the cleats worked with other pedals.
I binned the ritcheys.