There's a nice bit of software called Solaar that offers similar features on Linux to Logitech's pairing and management software for wireless keyboards and mice, and most usefully on the one I'm currently using it lets you switch the default for the top row keys to be normal function keys rather than shortcuts.
I like wireless for keyboards with a desktop but not mice, as the latter tend to eat batteries, feel heavier in the hand and be smaller than normal mice which leads to claw hands and RSI. So I picked up a couple of cheap MK270 keyboards that are normally bundled with M185 mice (neither with the USB receiver dongle) after verifying with Logitech's product fact sheet that they use the unifying receiver tech like the K400r I'm typing on at the moment. They also specifically state that the K270 (which is the keyboard part of the MK270 combo set) uses their unifying receiver tech (i.e. one dongle for up to six compatible devices).
Bollocks do they. After some investigation it turns out that the early releases of the MK270 set did, but Logitech haven't withdrawn the inaccurate data sheet. Elsewhere on their site they indicate that the premium MK540 sets use unifying tech, but the cheaper MK270 and MK295 sets don't have that 'unifying' bit in the connectivity description. So somewhere along the line, they've deliberately nobbled the hardware without bothering to change the model number – the design has been around since 2011 – or update the rest of their site. Or are selling variants in different territories, perhaps.
The first clue was Amazon reviews: "Logitech has done something very strange here. They have two different flavors of their K270 keyboard. One uses their unifying receiver technology, the other doesn't. The keyboards look identical except one carries the MN number Y-R0015 and the other YR0042. The former is Unifying, the latter is not. I have tried to use the non-unifying version with a unifying receiver – they will not pair."
There are also two variants of the nano receivers, those for a single device (mouse only) or combo sets (mouse and keyboard) and cursory testing (as well as feedback from other people) is that the former won't take a keyboard instead of a mouse. Even if you get one of the latter (I found a dual device receiver on eBay from a Shenzhen seller stated to be for MK270 keyboards with serial numbers starting from SN14/15/16 onwards which these are) there's no guarantee it'll work. The one I got was recognised by Logitech's own software and Solaar but wouldn't pair with either keyboard. (Update: got one to pair with it and a M220 mouse. With different brand batteries and on the second attempt, which suggests the keyboards may actually be slightly defective with a weak pairing signal. After pairing it works, though. I'm typing this with it.) (Update 2: it stopped registering key presses reliably. Further reading showed some people had problems with their MK270 set keyboards around Bluetooth signals, which does fit the pattern here as I'd recently plugged in an adapter to use with some earphones I normally use with a tablet. Considering how prevalent Bluetooth and other wireless peripherals are, this is extremely poor design and testing from Logitech. Oh, and other reviewers indicated their keyboards only worked when the adapter was on a USB extension cable next to the keyboard.)
If you dig around on their support site, Logitech will sell you a receiver (P/N: 993-001106) for fifteen quid plus another ten for postage. But the full sets are just over twenty quid new on Amazon, which means that (even assuming those ones work) that by switching to not bothering to use its own unifying receivers on cheaper sets Logitech is pushing people to throw away working hardware, hence the title of this entry. You'd hope to see some regulation in this area and tech companies required to supply parts for repair at cost, plus a big company making sure that wireless hardware works around other common hardware.
Mind you, you'd also hope a convicted monopolist like Microsoft wouldn't get away with releasing an OS that deliberately won't run on a majority of existing PC hardware, with climate change fallout continuing to make headlines. Big tech continues to demonstrate it won't act against the profit motives of forced obsolescence and blocking repair options unless forced to.