I've just upgraded the motherboard, CPU & memory on my PC, then imaged the current boot drive to an m.2 drive and it all just worked without having to reinstall or even repair Win 10.

For those interested, I've gone with a Gen3 Ryzen 5 3600 processor on a Gigabyte B450 Elite board with 16Gb of DDR4 3200 and a 480Gb NVMe M.2 SSD.
This was replacing an old AMD FX-8320 that I'd had for 4 years and Windows seems to have sorted itself out without any real issues so far - it just booted up and spent a few minutes removing & installing drivers.
This is easily the least hassle I've ever had doing an upgrade - usually ends up with a broken operating system and a clean install...