Lube will help, something like waterproof grease so rain doesn't wash it away.
WD-40 is useless as a lube. WD stands for water
displacement and got its start after a
hurricane in
Texas. It's made to dry out breakers/electrical
equipment and evaporates quickly leaving very little
oil.
Suppliers that cater to machine shops have many bushings of different metals and sizes. Probably available on line. It's not that difficult to drill out the
aluminum and insert a bushing of a more durable metal. If you do it right, you freeze the bushing and when it's installed it expands and makes a tight fit.
Or find an aluminum shackle and hook to it. Each will wear, but takes twice as long.