If I don't have time, what's the quickest way to get the most back from selling my stuff pre loved ?

I would suggest for you to post on various preloved sites, carousell, facebook preloved pages, gumtree. In order to get the most back maybe a challenge. However if you can check the price of the item others are selling, you can lower it slightly and it would sell faster. Tested and proven, works great. Do note that the items you choose to sell makes a differance too. I have tried selling kids stuff and even household items. They are taken within a couple of days and if you are lucky maybe even within a few hours. All the best.