I currently have: 2009 13" MBP, 2010 21" iMac, 2012 11" MacBook Air. None are powerful enough for video editing as I (learn how to) edit 4K videos from my DJI Mavic Pro (awesome piece of kit, btw!). I'm also an aspiring photographer so I want to dive deeper into Lightroom, photo editing, etc. Find the 15" to be too big/heavy so I prefer to stick to a 13" with Retina display. Official refurb would be my first choice, followed by second hand. Personally I want minimum of 512GB storage and 8GB RAM (16GB would be wise as the RAM is not user-upgradeable anymore?) but beyond that I'm not sure about CPU (i5 vs. i7, clockspeeds, etc.). What minimum year/specs should I be looking at? Thanks!