Have you looked at the 50+ forum or any of the subforums for older riders
https://www.bikeforums.net/fifty-plus-50/? You are not alone at 80 still riding but certainly a diminishing number. It is true that a recumbent is often the solution for the aches and pains that come with using a DF bike. The good ones are not cheap but certainly do make riding more fun when there are fewer aches and pains to discourage riding.