Do you know, how to spend "OP_SHA256 OP_CHECKSIG" TapScript? Is it spendable at all?
As far as I understand, it requires "<signature> <message>" as an input. And then, the hash of the message could be converted into x-value of the public key. However, after reading
CAT and Schnorr Tricks I, it seems it could be possible, if the "<message>" would contain for example "HASH(G||G||txdata)".
Also, because any "<signature>" is just a combination of "<r,s>" values, it could be a combination of "<r1+r2,s1+s2>". Which means, it may be possible to create separate signatures upfront, and then join them in this way, just by tweaking some values. What do you think? Do you have any ideas, how to spend that TapScript?
