What you are referring to is proper "parquetry" and the labour is generally costly as it requires more attention to detail and is more time consuming... you may be able to manage cost depending on your choice of timber (note parquetry now also comes in engineered timber which can be a bit less) but the labour will be costly regardless... my google search of "parquetry flooring Sydney" came up with a few results so hopefully you can find someone there after a few enquiries... good luck! :)

Consider a burnished oil finish. I believe this to be superior to layers of polyurethane which often cause boards to stick together and show the scratches. It allows boards to expand and contract. If scratched just use oil over thecsctratch and it will disappear. This would still be done by a professional.

i was once told that "any wood matches any other wood" and that's helped me live happily with mismatched timbers for many years..of course it's probably possible to sand and stain the floor (ask a laminate timber floor supplier) but it'll be a tedious waste of sweat and tears for an uncertain result..what about make sure the walls, ceiling, architraves and skirting boards all look great and don't worry about under the hearth if it's not being moved, maybe add a matching trim around the hearth and plan a new floor for "later"

Our last house and our current house both had wood floors and lots of wood furniture. Using area rugs (I've got a weakness for oriental rugs) provides separation between the floors and the furniture. And if the walls are light, as in LesleyH's photo above, you will certainly not feel overwhelmed with wood. The only time there's an issue in my mind is when the walls are also wood clad - that can be a bit confronting and needs management.