If by 3OP you mean 3-cycle orientation + permutation then you're actually going backwards. You'll have to memorize twice as much information for the memo of corners and the execution is very inefficient.
Learn M2 since it is very very similar to OP. You're just using a different buffer (DF instead of UR,) doing slightly altered set-up moves to a different target (UB instead of UL) and doing an M2 move instead of T/J-perm. Plus once you're good at M2 it provides a good way into learning advanced M2 and then commutators.
Look into learning some BH/3-style algs for corners. You can get by off 12/13 algs for each type of corner case and doing appropriate set-ups to each!