>>1733995wider tires
smaller wheel diameters
wider hubs
wider seats
in terms of gears, more teeth = more strong .eg 42x11 will wear out much faster than 61x16 or 65x17 (tldr if you can get the same gear ratio while using more teeth do so)
you might not be biking very fast but consider better brakes
rim brakes with a high mechanical advantage, being careful not to over heat the rims or wear though them
or
a good brand of hydraulic brake that support rotors 160 mm or larger
aside from not having very good brakes and being somewhat heavy, a beach cruiser fits most casual use
its not going to be fast or anything like that, but its simple, comfie and durable
>>1733998aqua jogging mite be a good starting point, being low impact on joints and enjoying cool water is nice
just dont over do it or ye drown