If you hate having to manage Windows and dislike being responsible for looking after the OS then you will probably LOVE the Mac. OTOH if you hate not being in control of how your computer does stuff and like to have at least some sense of knowing wat's going on then you'll probably HATE the Mac. Also generally Macs have no upgradeablility - generally nothing like RAM or hard drive space can be increased after purchase - what you buy is what you have forever with current models.
Mini-PCs are sometimes effectively a laptop in a small box without a screen, although with Windows machines you can usually change RAM and hard drives, but not too much else. Following the viewpoint above, if you are inclined to update graphics cards & processors, have multiple internal hard drives, a full-size PC is better. If desk space was very tight then a mini-PC can be mounted behind the screen in many cases.
If this also summarised your approach to computing generally then a Macbook Air or a Mac mini may well be the most cost and hassle effective machine for you. *Personally* I would tend to buy a pile of bits and build what I wanted - I enjoy the process - but from the sound of things, you'd probably enjoy something that just looked after itself and got on with it. As suggested, if you buy the mini, spend at least £300 on a half-decent 1440P 27" screen too, although with Black Friday deals you might get something good for less. Make sure it's IPS technology and 99% sRGB colour gamut.
Any of the current Macs with an M series processor would be OK for photo editing, but DO NOT buy a used Mac with an intel processor, because they are now obsolete.
