I had to settle for a shower for years and years because the place we lived in only had a shower although my showers are deefinitely not a three minute person, more like 15min ha-ha I too decided on a spa bath in our new build, one that is big enough to fit two people but is simply a bath shape and I'm finding it hard to get myself back into baths because of being used to a shower for so long but I don't regret it either. I used to read the paper in the bath back when papers were what was around back then and I do miss that ha-ha

I think your house could be lovely with a bit of spit and polish! As per the previous comment, a paint job would do wonders. Our house is similar in that the ground floor is brick and the top is (now) weatherboard (over fibro). We lived in the old fibro for years before we could afford to renovate. It gave us more of an idea of what we would ultimately like. Here is our before and after. As you can see, we added a deck and changed part of the the roofline too.

with 22m to the rear boundary my suggestion would be to build a separate dwelling using a variation of the house plans on the yourhome.gov.au website and connect the two building with an extension of the existing covered deck to make a shared alfresco...the new building would have a raked ceiling with the roof sloping down from north to south.. the web site has detailed plans and specs suitable for Adelaide that a builder could use to estimate costs eg 150sqm @ say $2000-$3000 per sqm depending on materials and quality of finish and contingencies but you'll need to discuss your ideas with council as there's also a restriction on the total area of the block that can be covered with buildings but something like this could work with the mancave extended from the carport but you also need to ensure enough light and view into the family dining and kitchen

At a time when prices are rising for both building materials and furniture, it seems that it will not be possible to finish repairs immediately. The kitchen is considered one of the most expensive rooms in the overall furnishing estimate. We asked designers which items could be cut. In many respects, the opinions of the pros agreed, which only proves - the tips "working." They can be used. Any custom solutions are more expensive than the standard ones. Even a modular kitchen can be built in if you make a niche for the given dimensions in advance. Try to abandon some of the hinged cabinets and "mix" the kitchen set with open shelves - it will save your budget significantly. Also, don't forget the trash. If you have a small kitchen, it shouldn't take up much space. It's best to buy a can crusher at https://www.amazon.ca/HomeBuddy-Can-Crusher-Recycling-Aluminum/dp/B08D6QV6B5 in all, these are the basic tips I can give you.