I like to think I am still young
but I struggled with this as well. I am a woman with a little less arm strength. I had the same problem you describe on my first catamaran boat flip yesterday. My son who is 12 seemed to have no issues but my 10 year old very athletic daughter and I had to work at getting back on our Hobie Getaway since it sits a bit high in the water... I created an adhoc rope ladder but like you said it swings under the boat which still then requires substantial arm strength to pull yourself on.... ended up using the wings. Hooked my foot up and over the support bar and then flipped up under the seat. Was not very graceful, but did the trick. I am a mechanical engineer by education (not in practice these days) but sketched out a simple design to ease reboarding and if it works I'll send you the details.