A WiiM Pro Plus streamer and DAC plus the Fosi V3 amplifier would come in way under the Cambridge Audio on its own leaving the lions share for speakers or speakers and a sub. This would produce far better sound any day of the week.
In my view a buyer would do MUCH better to spend £30 more and get a Wiim Mini and a Chord Mojo 2 DAC to replace the Cambridge MXN10. A streamer does not have to include a DAC, in fact it is preferable that it doesn't. The digital stream of 1s and 0s from a Wiim Mini will be identical to that from the digital-out from the MXN10 for £370 less and you can then choose your preferred DAC, and there is nothing out there to beat the Chord at £395.
I have owned the Chord (Mk 1) in the past as a fixed DAC in my hi-fi. I have since replaced it with a second hand Chord Qutest for £1k which was much better sounding, while maintaining the same basic Chord character. It is fed by an old second hand Sonos Connect streamer (Gen 2, compatible with their latest app) that cost me less than a new Wiim Pro, and is compatible with many, many more streaming services than either the MXN10 or the Wiim.
Assuming it is technically competent, the most important aspect of any streamer is the services it supports. Sonos supports more than any other on the market, so as long as you only use the digital-out sockets there is no reason why it will sound any different from any other streamer through an external DAC.
And my combination of cheap second hand streamer and top-notch DAC sounds stunning!