Road King Used purchase Differences Year of construction

Hello dear Harley friends, I am the Sandro and I am just selling my Fat Bob FXDF to give me a Road King. Now I wanted to ask from which year of construction it is highly recommended or which year of construction would be rather less recommended.? And why? I have a budget of 20 mille possibly 21 but less would of course much prefer ?? and if there are perhaps no big technical differences but for that pricey then it would of course be better to have an older one But technically, it’s absolutely okay. Has anyone had their experiences like this?