We installed a Dotline folding deck-mounted ladder. Ours is 6 steps. Sue bought this for me after our first half-season with the boat as it was an essential item. Our boat didn't come with a permanently fixed ladder and it was supplied with one of those plastic ladders that hangs over the side. It was never intended to be a permanent solution, but it has lasted for 11 seasons so far and it looks exactly the same as it did when it was brand new. Ours fit just inside of the stern rail opening, like it was custom made. It has 3 rungs under water when deployed. When folded up, the hinge is just above waterline when at rest. The hinge does drag in the water when underway, both motoring and sailing. It's never bothered me in that regard.
It is very important to have rungs under water for access. 3 rungs is about right for me. Also, the loop at the top of the ladder is critical for getting a good grip to pull yourself over the gunwale.
It is meant to be hung vertically. I had to adjust the mounting point and cut the standoffs to get as close as I could to vertical on my reverse transom. It does require maintenance. Every other year I need to replace the plastic pads that are inserted inside the aluminum tubes where the open ends close as the ladder is deployed. I don't know if they make the pads. I find plastic pads at the hardware store that I have to fabricate into the right shape. Also, the rubber shoes for the standoff tubes have to be replaced frequently as they disintegrate in the sun. These I also get these at the hardware store.
We bought ours from West Marine, but it looks like they don't sell this model anymore. I see that Defender has it. The 5-step model may be a better fit for your boat.
For a little more than $100, this has been economical and one of the most utilitarian parts we have ever purchased for our boat. BTW, the pushpit is the stern rail.