bip 85 question: could you derive a child seed phrase on a Cold Card from your main seed phrase.  And then take that child seed phrase,  load to the cold card and use bip 85 to make a child from that seed?  Essentially a grandchild seed phrase.  I was thinking of just creating that to use as a back up wallet in case of emergency.  If this is possible, my other big question is- would there be any quick and easy way for a bad actor to find that seed in the event the main seed  (grandparent seed) was compromised.  Obviously they could if they had tons of time and/or knew what they are looking for.