I don’t recommend bikes for older riders. Too easy to get injured in an accident under most usage conditions.
I have thought about recumbent tricycles – possibly arm cranked for more arm exercise. Maybe electric motor assist for serious long distance commuting. It is clear that the engineering optimal design has not been solved – they look awkward. Complicated by the fact that cities and streets are not well designed and are growing in the wrong direction like the fat slobs that live in the cities.
All wheeled vehicles deprive humans of needed walking for optimal brain function. You need about 10 miles per day of walking to get the 3% per annum brain growth. Also time walking reduces time sitting which is very destructive for health. Bicycles may lead to more sitting if you do not walk enough after bicycle rides. Most bicyclists sit (I usually stand on the pedals).
All rubber tires kill electrical contact with planet earth that is needed as a source of electrons. After using a bike or car you need to swim in a lake to replenish your body’s electrons. Triathlons figured that out, especially if you run barefoot or with leather soles such as the moccasins used by my native american ancestors. Horses with iron shoes provide some electrical contact with the earth. Buildings and vehicles need re-engineering to improve electrics.
Wikipedia has good articles on tricycles hand-cycles velo-mobiles etc.
Wikipedia pages load fast indicating that they do not contain advertisements, spyware, trackers, web bugs, excessive images and formatting,…. Usually provides a good overview with many footnotes and references to help locating details without using dangerous blogs and search engines such as google.