I did literally the same. I often buy and start games but don't actually end it but I've got better at ending them lately. It's taken me a long time to complete Wildlands. I originally aimed to do everything but I think collecting everything and doing every side mission (those are very repetitive, stealing a plane or raiding a building etc) made me bored and I quit for months. Then yesterday I picked the game up and exclusively played through what was left of the story missions which I had loads left go do and I absolutely loved it. I actually knew what was going on when I did it this way! I will give breakpoint a chance but yeah I don't think it'll be the same as taking down the cartel. I got really invested in that!!! I also liked having 3 AIs as backup / company which breakpoint is currently lacking I think.