Since 2-channel is important, going with an integrated amp is the way to go because you really don’t want the cheap and compromised preamp section of a mass market AVR being a bottleneck and mucking up the sound, and preamps matter a lot!!! I’d recommend this Hegel H190v integrated as it sounds great and includes a very serviceable streamer and DAC so no need to spend on the Node, and it’s $800 cheaper than the Rega. So between the Hegel being cheaper and not having to buy the NodeX you’ll be saving a big chunk of $$$, and you can obviously upgrade the streamer and/or DAC down the road if you feel the need, but you may well be happy just using the Hegel alone at least for a while anyway.
https://www.audioadvice.com/products/hegel-h190v-integrated-amplifier
I’d stick with the KEFs because you’ve heard and like them and would definitely not mix brands especially with the L/R/C speakers, For an AVR I’d recommend this Yamaha both for its sound quality and because they offer the best reliability in AVRs, which is not a small consideration. I compared a Yammy AVR directly to comparable Denon, Marantz, and Adcom models for 2-channel performance using my reference recordings and $9k speakers and found it by a good margin to be overall the best sounding of the bunch. You’ll get great value by buying from this reputable seller.
For a subwoofer I’d highly recommend this Rhythmik F12G that many here have bought and are thrilled with and will give you much more than the KEF sub for not much more $$$ because they sell direct so avoid the considerable dealer markup. You should talk to them about multiple input options to accommodate both the AVR and Hegel being hooked up to the sub simultaneously so you can use it for both 2-channel and HT, and they’re very helpful and informative via phone.
https://www.rythmikaudio.com/F12G.html
Ok, that’s my long-winded recommendation. Hope it helps, and best of luck in your quest!