bip110 doesnt freeze previous utxos.
AND also previous to announcement of bip110 there was no utxos deep enough to be frozen by bip110, it has been checked before. if it exist now, it has been created knowingly. to make up a point.
OP_IF also defeats the whole purpose of taproot. which is using leafs. if you are not gonna use taproot as taproot, dont use it.
also i wanna share some clips:
36:56
https://www.youtube.com/watch?v=yEZmJizKZWk 22:45
https://www.youtube.com/watch?v=JPE7X_q3A7A