I recently went and replayed the DLCs of AC3 and Odyssey, which I’d quit for various reasons. Particularly in the case of Odyssey, Open World Fatigue played a role: I couldn’t be arsed to explore everything anymore, but neither could I bear to leave anything open.
I decided to just go for the missions, to not worry about over optimising my choices, to not worry about cleaning out every little question mark and chest and finishing every location. I finished them, enjoyed my time and found new freedom in not having to draw out the maximum amount of game time for my money.