You're going down a rabbit hole, but for pressure washers this is pretty much the go to for the entry level in the detailing world. I've had mine for probably 2 years and it's still going strong. You really don't need a stronger one if you're just doing your own car.
I recommend something like a flexzilla hose and a stubby gun like this.
Get some quick releases, put it all together, and buy a pack of the white 45 degree 3.0 gpm nozzles.
Also, absolutely do not let hard water dry on the car. The minerals in the water will eat through your coating and paint. You'll need to dry it with a towel and detail spray, the spray will lubricate the paint while drying it.
I highly recommend watching the AMMO NYC detailing series, it's the best way to go about this.
It would take a whole page to go over detailing products, you'll need to just try some and see what you think, then try a different brand, watch reviews on products, etc. Stay away from chemical guys, turtle wax, maguire, etc. Weirdly the only big name product line that has reliable products is some of the items from Adam's like their shampoo and foam are easy go to products. Extremely cheap and still great to use.
You'll also need a foam cannon lol, the list goes on. The foam cannon is important because if you rinse the car off with water that hard water is going to dry on the paint before you can get the soap to it. So you want to rinse the paint to get loose dirt off, then foam it because the foam will neutralize the hard water and make it safe for the paint, do a 2 bucket wash, rinse it and dry as fast as possible with a good lubricating detail spray. The AMMO NYC hydrate is a good one, but each brand has their own and they all work well. I use McKees 37 graphene detail spray and it works great and puts a light protection. They all pretty much do the same thing, thats why you use one until it's gone, buy a different brand, see what you think, and then you end up with 3 shelves of products like all of us.
Big note: obviously only use microfiber towels, that's a whole subject. If the towel touches the ground, put it in the wash bin and get a fresh one. Only wash them by themselves, don't let them get dirty so store them in a sealed container like a storage bin, the rags to riches soap actually does work really well to restore them. When you're folding them just quick check for any loose debri, sometimes you'll get a little bit of something stuck in there.
Microfiber towels are probably the most sacred item in your collection. They absolutely cannot get dirty because the dirt in the towel will scratch your paint.