What size wheel and tyre on the car?. A higher spec or sportier trim will have larger diameter wheels with low profile tyres, these will give a harder ride (due to shorter stiffer sidewalls), more noise (more rubber in contact with the road) and worse mpg (ditto, plus, potentially a stickier rubber compound).

If you really like the car otherwise, consider buying a set of smaller wheels (second hand) on which can be fitted narrower tyres of a smaller diameter.

The front tyres are pretty much done, so maybe worth replacing then with some new mid range.

When I bought the car, it was fitted with the 235/65/R17 budget all season tyres, it's pretty new tyres, on the rear have 7mm grip, the front has 3mm. As the profile of this tyres is already high, I don't think changing the tyres to even premium one will make a significant change, but I might be wrong...

The tyres surely can't be that new if the fronts only have 3mm of tread left. That is about when I'd be thinking of changing them!.

But yes, tyres of that size shouldn't be the cause of the poor ride. But they are fairly wide, so would certainly contribute to noise levels, bearing in mind some tyres are noisier than others of the same size. Having the pressures too high would make the ride harsh, but I'd have to assume you have checked?. Only other thing I can think of is that the tyres have a higher load rating than necessary, which (in theory) would mean a heavier and stiffer rubber compound. But even then, I wouldn't expect the difference to be that big unless the weight rating was way higher than it needs to be.

You have not said how long you have owned the car, but for me, the presence of budget tyres would have put me right off it. If the previous owner has cut corners on something as important as tyre quality, where else have they cut corners re servicing and maintenance of the car?.

But it sounds like you will just have to put up with the poor ride. The noise, as was mentioned, sound proofing kits are available and that is something you could do yourself, though it would be a very fiddly job!.

My last set were Kumhos from memory. They started to become very noisy when well worn - a change immediately made the car quieter. At the same time make sure the tracking has not strayed outside of spec.

I think brand-new tyres will always sound quieter than well-used ones, as rubber slowly hardens with age, especially if it is exposed to plenty of sunlight; and of course the tread becomes shallower. The process is normally imperceptible, so only noticed when new tyres are fitted !

I have already dropped tyre pressure from 32 to 30psi, but don't feel any difference. Maybe all the rubber bushings of the suspension hardened and give such firm ride..

I would have thought that bushings would be too thin to soften a rough ride caused by the road surface - they are there to prevent bodywork noise. Most work will be done in flexing tyre sidewalls, hence the harsher and noisier ride from low-profile tyres.