IMO running a Windows machine of some description together with CumulusMX is the easiest option if (i) you're used to Windows and (ii) not at all familiar with eg Raspberry Pi. The Pi is a great little computer but has 2 drawbacks:
The main one is that if you've never tried running a Linux computer before then there is undeniably a significant learning curve. Linux (eg in the form of Raspbian which runs on the Pi) is not difficult to learn but existing Linux users often underestimate how unfamiliar it feels to a Windows user at first acquaintance and why non-techy users often feel a bit out of their depth to start with.
Second, while it's true that a new Pi itself costs only £30 or so, you do also need various other bits and pieces to run the Pi, like a good mains adapter, SD card, maybe a case and then a keyboard and a mouse. None of these items is very costly and you may have some/all of them already. But if not then the cost does add up and you'll end up spending more like £50-60. And this is without a screen and HDMI lead. Again, maybe you'll have a spare one available, but if not then there's another chunk of cash. (There are ways of running a Pi remotely - what's called headless - and controlling the Pi from another PC. Again this isn't difficult and it's certainly a more elegant solution, but it's probably not the first thing that someone new to the Pi wants to learn, so let's assume you'd prefer a screen for the Pi.)
But there are also a couple of other issues that may apply to any small computer. SD cards (or USB sticks) are not reliable memory stores, long-term - given time they probably will all fail in the end. So it's really important to back up your data regularly to another storage medium.
eMMC memory is difficult to call because the detailed specs are rarely disclosed. It's likely to have somewhat better memory controllers than eg most SD cards and so probably a better life expectancy, though probably still uses cheap TLC memory. But it's not going to be as good as a modern SSD or conventional hard drive in terms of reliability.
And there may be something of a question mark over keeping a laptop plugged into the mains continuously. I have seen recommendations that it's best to remove the laptop battery to prevent damage to the battery, but how necessary this is I don't know.