On noise, this is what I suspect, too; thus I am not trading in a couple of HackRF One-s that I am currently playing with. Still would be useful to know the numbers.

On the range, I did not pay much attention (but maybe I should have): the power of HackRF one is low, too; one needs an amplifier to transmit in the open air anyway. Do you think that the rpitx TX power is not suitable for table-top sized prototypes?