You might not need the Nihola Flex shown in the image above, but at some point in your life, whether as a child, adult or elderly, you may need some special adaptation so you can continue to bike. The Nihola Flex, by the way, is imported by Curbside Cycle; speak to my friend Eric who has always pushed the boundary of city and practical cycling. I've documented who carries special needs bikes. Here are a few:
Wike has for a long time built quality bike trailers for kids with special needs.
While specific needs bikes are thankfully becoming more mainstream, you might still be able to find someone who could build a custom solution. Manuel Cappel, a guy who lives in the bike-centric Toronto Islands, has built a number of cargo trikes where an adult can sit comfortably in the large box while the person behind pedals them around.
I hope you can find something that works for you. If you discover a solution I haven't listed please let me know and I'll update things.