Are you saying that we should be combining two sources of randomness or that it's already happening in the background? Is that what the Coldcard and Seedsigner are doing when you input dice rolls into the devices to generate your seed?
It's already happening in the background on Coldcard -
https://coldcard.com/docs/faq/#entropyCan you provide a few examples?
Every time you roll the dice, also flip a coin. If the coin lands heads, keep the dice result. If the coin lands tails, invert the dice and record that result instead.