Honestly I think OP will be better off just buying Minisforum HX99G - for 700 you get 6900HX, RX 6650M, case, psu, motherboard. No point really in looking into diy for a small pc with entry level cpu.
That thing looks fantastic.
Please remember that any mention of competitors, hinting at competitors or offering to provide details of competitors will result in an account suspension. The full rules can be found under the 'Terms and Rules' link in the bottom right corner of your screen. Just don't mention competitors in any way, shape or form and you'll be OK.