Poison drops off as soon as you get to the harder content. Most poison monsters don’t do enough damage. There are exceptions of course. Blood moves and piercing moves are mostly what you want. For example, Angelion will perform very well with raw bloodfury, while Momo in 2nd form will struggle with faststrike (it has low attack stat) but if it’s awakened it becomes fastbreaker which easily piercing one-shots enemies.
I highly recommend you get Mantisamurai as soon as you can. It’s from evolving a 0* monster (Mantisword) and it’s extremely powerful. It’s also something that can be built around easily for PvE content.
I plan to do a re-write of this soon to update it and give some clearer advice, but it probably has some useful things for you: KD's New Players Guide