If you do want to use Oppression in Monarchs, then I suggest going with a different build and different choices. Oppression in Monarchs screams Treeborn Frog, since that little guy doesn't get affected by Oppression (if opponent Oppresses it, it can just try to summon itself again). Therefore, you could keep Oppression and switch to a less synchro-based deck, and more of a Treeborn-based deck. I will give you a framework (not a full 40-cards) and you can fill in the rest as you like:
Monsters(17):
3x Caius
3x Raiza
1x Thestalos
1x Mobius
2x Light and Darkness Dragon
2x Treeborn Frog
3x Swap Frog
2x Cyber Dragon
Spells(9):
3x Soul Exchange
1x Brain Control
1x My Body as a Shield
1x Lightning Vortex
1x Mystical Space Typhoon
1x Heavy Storm
1x Foolish Burial
Traps(
:
2x Oppression
1x Solemn Judgment
2x Bottomless Trap Hole
1x Torrential Tribute
1x Mirror Force
1x Call of the Haunted
That leaves room for you to personalize it with 6 more cards. You can use Swap Frog and Foolish Burial to dump Treeborn Frog to the grave, then abuse him to summon Monarchs every turn and to summon LaDD once your opponent has few options left. Suggestions for other things you could add to the deck include Enemy Controller, which you can combo with Treeborn Frog to take an opponent's monster in the standby phase by tributing Treeborn, then since it is still Standby Phase you can summon Treeborn again, thereby giving you basically multiple copies of Brain Control. You can use this combo to summon LaDD very easily. You could also use Gold Sarc to search out necessary materials, and Pot of Avarice if you want to be able to re-use certain cards. Almost all of the summoning in this deck is unaffected by Oppression (just Cyber Dragon and CotH) so you'll be able to run it and flip it without fear.