Can USB Keyboards Spread Viruses And /Or Malware ?

I keep all items I purchase from new to scrap unless they break.

I run mainly Windows 10 but also use my old Windows 7 machines. Both connect to different Internet suppliers and nothing of a financial nature etc is used on the Windows 7 machines. I do not share USB sticks or USB drive enclosures etc between the machines.

However where I may have slipped up I did until recently use the same USB keyboard with all devices, stopped doing this but continue to use the same USB optical mouse on all my machines.

I asked Bing chat and from its results it was clear that it was possible to spread a virus via a USB keyboard or mouse but depended on various criteria.

Does anyone have experience of this ?
Thanks.

Any USB device can spread malware, but don't let these stories deter you from using a vanilla USB keyboard or mouse.

The USB spec allows multiple devices to live on the same bus (connection). What some security researchers (and actual sneaky products which are sold) have done is to add a second USB device hidden inside the keyboard or mouse. The second device operates on it's own, and tries to trick unsuspecting users when it gets plugged in. Windows is informing you there's a new device, but uninformed users will think it's just a nuisance warning.

Some fancy USB gaming keyboards can fall into this category. For 99% of the real-world, your "dumb" USB keyboard or mouse only functions as a basic input device and cannot transmit any malware.

The keyboards would need to be "infected" from the manufacturer on ... and I can't see that happen.

Otherwise it would need to pass the computer anyway (because I don't know about keyboards with internet access by themselves). And that without actual power ..

Then again if powered by USB;
USB-C can transfer netwerk data, and USB-A can't. Right ?