you could go to town fixing everything and cleaning/straightening it all up...... but you'll end up renovating a lot of the house and it will be a relative expensive exercise for just a tidy up........how much do you want to spend?.........an obvious change would be to get rid of the centralised walk-in pantry, access laundry from kitchen and streamline the flow between the entry and lounge

The 45 degree angled walls are actually an efficient way to help with circulation. Squaring off all of these angled walls will not make the house seem more spacious, but probably less spacious, and at considerable expense. When moving walls you also have to consider what happens to the ceiling, cornices, skirtings and floor finishes where the old wall was located. It is a messy, fiddly, and labour intensive process for small changes for no improvement. Spend your money where it counts as Paul Di Stefano Design has suggested above.

Best of luck,

Dr Retro

of Dr Retro House Calls

maybe widen entry and keep study setup as a smaller narrower space behind folding or double sliding panels that you close off when not in use....then you retain the function......perhaps even access it from the lounge side, or from the current WIP side.....a few options but with that budget you'll be pretty much contained to just the entry/study rejig and kitchen/laundry rejig and associated collateral to connected spaces

we need measurements of all the rooms and please show location of any garage, boundary fences, direction of north and the best views and do you have any outdoor entertaining areas or verandahs, what are the walls and floors made out of and describe your climate

Looks like a beautiful property

anything is possible with the right price but if the property suits your needs a timber structure is much easier to alter than brick walls with concrete floor so consider location and price first as a house in reasonable condition can usually be modified to be more comfortable but keep in mind that a house on acres has different lifestyle than a house in the suburbs eg you may not need a formal front door as friends and family will usually arrive at the garage and parking area and come into the house through the back door so adding double entry doors to the study will open up the space without removing a wall or changing ceilings and the entry hall might squeeze in some bookshelves to add some extra storage to the study while keeping access outside without changing the front door...and depending on accurate dimensions it should be possible to rearrange the kitchen but it's usually best to live in the house for a while before deciding on renovations to a new home...it's quite possible that the rear deck and verandahs may make the house cold and dark at different times of the year and it may be more cost effective to rearrange some of that space before removing inside walls