I only used the example of my own folding Fiido D11 in post #12 to illustrate that e-bikes with full throttles are available, even if not legal.Yes sorry my mistake I copied that in cyclebuddys post all this is getting me confused
I considered the Rambletta and Stow-E-Way (among others) when I looked to buy my own folding e-bike, but chose the Fiido D11 over all others because my purpose is to commute using trains: The Fiido trolleys better (pushes along a station platform when folded), is lighter in weight for carrying/manhandling (17kg), and has a larger battery (11.6Ah). Those factors were the most important, overriding factors for me, but don't apply (won't be as important) to you.
I also have a VW T5 van with another e-bike for trips away cycling. My choice of e-bike for that purpose was completely different.
Those e-bikes on your own shortlist are likely better choices for what you need, although I do think the battery of the Stow-E-Way/Evo is going to be too small given your knee issue and thus you'll be using higher levels of assist a lot of the time.