paint stripper primer and rust oleum.

spray paint BAD.

brush washes new and old finish together

spray just puts on a film

leads to peeling as shown in photo

just look at this as changing oil in your car, metal railing is
maintence issue

metal rexpands and contracts a lot leading to pint cracking

long term solution is outdoor wood stained, changes repair cycle to
very long recoating stain is easy