We have the black mirror splashback. We love it and it soooo easy to clean

on the landscape plan - The road frontage is the left hand curved side & the black rectangle is the position of the outdoor fire.

I would clean up first. Especially the stuff growing in the paving. Then get gardening with pot plants and start experimenting with different plants and the positions. See what you like and if you can keep it alive! Our house has the sun setting over the back fence and we've done a few inexpensive things to reduce that issue (most expensive were outdoor blinds around the verandah) but for most of the year we just don't want to be out there. It is hard work to keep the plants going in summer, there is a lot of sand due to the difficulty in keeping lawn alive and it is just bloody hot. So, that's why I'm saying clean up, start gardening small and see how you go before committing to structures that might not address the real issues you have with the yard. Just my 2 cents! :)

You could install racking for both sides of the room, toys & clothes that aren't being used can go into large plastic containers with lids. The two bikes could be hung from the wall or ceiling. And yes, anything that doesn't need to be there, move it on. There are so many hooks and storage options available that it would be very easy to sort this out and by getting a lot of it off the floor.