That's a cracking DIY job.
It's difficult to get back into any boat, esp if you're clothed and after the physical shock of an unexpected dunking into cold water.
You may recall 'The Fisherman's Apprentice' a few years ago in which Monty Halls jumped in to see what would happen. Something of a struggle & IIRC he said that two or three attempts would be about as much as he could manage. Bear in mind that he's a former RM & a diver so his fitness level is going to be pretty good.
Rope ladders with or without hard rungs tend to swing under the boat as you put weight on them.
My dory has low guardrails both sides on the rear half of the boat which makes the side higher.
I have a permatrim on the outboard cavitation plate and that makes a great step when you know it's there.
Having watched a RN winchman climb into mine over the stern and seen the effort involved - he didnt know the permatrim was there, the noise of the helicopter made speech impossible & hand signals weren't understood - I bought & fitted a folding ladder just in case I go for an impromptu swim.
Force 4 3 Step Boarding Ladder - 1 Fixed/2 Folding | Force 4 Chandlery
Has been tried & tested & it works.
Appreciate transom space is going to be more of an issue with smaller ribs but well worth looking into some sort of device capable of deployment by one person from in the water as a 'just-in-case'.