I am 77. For improving balance and stamina I do " rebounding" = very gentle bouncing on a personal trampoline where feet remain in contact with the trampoline. A handle can be installed for maintaing balance/ safety. Very safe and handy plus great for The Rocky Mts. weather.
For walking indoors and out I wear "barefoot" shoes which are very comfortable and easy to put on/ off.
I puchased the above items from Temu. They have a huge selection of the shoes and very good return policy.
The trampoline was only $50.