Replace, don’t repair is likely the best choice.
I got an Alumacraft from the 80’s two years ago. First time on the water I leaned back and just kept leaning back. Repair seemed to be at least the cost of replacement so I went new. I wasn’t interested in anything fancy and caught a sale from Cabela’s.
The funnier side of the story was my wife. I had wanted a boat for some time but kept telling her that they are holes in the water for money. Something is always needing help. Well, that day with the seat was the day the lightbulb came on for her. Now she tells her friends about boat problems and dollars down the hole