Share tactics known and unknown here.
I will share something that I discovered.
This is for the fourth and fifth floor of Peaca Intermediate dungeon, for those one-eye monsters.
You will want a tower cylinder for this and a lot of blizzard crystals with you.
Place a barrier spike and then install your cylinder. Target the barrier when the one-eye monsters come close to you.
The challenge will be how you will freeze the monsters before they get to you. There is a way but I will not discuss it since it seems like a bug. Also the chances of freezing this monsters at R9 is very slim, however it is possible to do so. (Not too sure about R1 frozen blast).