Wobbly steering

I’m new to Landyzone and I have a problem with my Discovery 4 and hoping to get some advice.
Around November I started to notice a very sensitive steering wheel and bit of wobbling while driving. Hard to explain but the car feels very floaty and unstable. I had the steering column replaced but no change. I’ve been to three garages and ends up in Landrover dealership. They confirmed thatthe steering rack needed replaced.
Garage 1 said it is my rear dampers
Garage 2 said it is my lower front arms
Garage 3 said it wasmy steering rack.
I’ve been advised to change my tyres and that will sort it. I’m not mechanically minded but hoping that members herecan point me in the rightdirection.

Are the garages specialists in LR products? The diagnosis seems to vary quite a bit.
Whats the mileage?

Have you tried rotating the tyres and see if it makes a difference ? https://www.4site4x4tyres.co.uk/4x4-advice/blog/may-2016/how-important-is-tyre-rotation

Sounds like the start of 'Death Wobble' ...

Just got to track down the suspension / steering slack ...

Swivel pre-load, wheel bearings, panhard rod bushes ....

Have a read through the Disco section, it's common and a pain ...

There is an article on just this topic in this months LRM that dropped through my door the other day. (March 2020 Page 38) The guy who wrote it said it was sometimes due to either a flat spot in the steering damper, i.e. for most of its length in both directions it works, but around the central part, i.e. the bit it sits in most of the time, there is no resistance.
Or it is the preload on the steering swivels. (Or they are shot.)
He did say of course that it could be anything (or things) in the steering system or front suspension, but if it is not obvious, try what is above.
Great article written under the heading Norfolk Garage which is sometimes the only thing worth reading in this mag! A guy who runs a LR workshop for a living, not just some journo!