[FTE217]

We know DFB will come in here and come up with multiple DIY tips (roK may have good ideas re the reataining walls) but here's my train of thought.
Yer PJ when your not a handyman makes it even harder but when it comes to saving $$ you got to put in the hard yakka - satisfying when done but yep you'll pay for it physically and moan and groan haha.

With split levels its hard yakka building retaining walls.
Cheap way is besa blocks as a thought but needing to dig a trench fill with concrete for the foundation.
Need to drill holes for water drainage in the blocks or you can space the base blocks a little. Agline layed behind the wall first off sand base, followed by blue metal then lay the line followed by back fill.

IF you couldn't be bothered doing that yakka you could turn the slope into a garden, plant natives or what suits the climate and lay down a 2/3 or 4 small brick curved wall, far less work compared to the above.

Edging/dividers for paths or borders.
I have used countless times pavers or bricks sideways up as borders, want it ground level you need to dig a little down so close to ground level - pavers I cement them down.
Easy job but tedious though well worth.
Far more durable than all these plastic borders you can buy fron buinnings nowadays.

Down the left side to pretty up,
comes down to how well you want it to look, making a garden bed with a front border similar as mentioned above but a straight line and how wide you like it to be.
Plants hide the fence thats a easy one to do tbh.

Overhang trees/bush's from neighbours side.
Well won't help heaps (for there is all the rest up high their side) but whatever hangs over your side of the fence you can trim it all back to the borderline, all you can do.

Got gurnie or karcher for the driveway ?
Many products to get to pour over then jet blast away.
Maybe that 90second product form bunnings will be enough - I have used chlorhine granuals with success tbh at times.
Hose down a section, get long handle course broom, scrub down then blow off.

Good luck mate look forward what you end up doing.