Hey PAPACHOSMAFIA

There are two things that come to my mind when considering higher rake environments in cash games in general:

1) Rake reduces the profitability of each hand that you play. In poker in general and in cash games you come across various situations and each situation holds different EV opportunities. For instance, if you hold a great starting hand on the button this looks like a clear ++EV spot before the hand starts because you can play many hands from the button which makes your opponents play more and weaker hands agains your actiont. So when you hold a great hand here it's a promising spot. Rake will take away a marginal amount of your expected EV in this situation but of course you will still play the hand.
However, there are also situations where the scenario becomes very close if you should enter the hand or not. In these cases rake will generally tighten your opening range compared to an environment with lower or even no rake. The very bottom of your range from each position might just become -EV and you are better off folding them. On the other hand, there is the usually weaker player pool at the micros. This in contrast can make weaker hands more profitable if very weak opponents act behind you. In most cases the extremely high rake at micros will force you to enter pots a bit more cautiously but keep in mind that special situations like a table full of weak players can counter this effect.

2) On most poker sites rake is only paid when a flop is dealt. This also includes when all the money goes in before the flop and you have at least one opponent (because the board will be dealt in this case too). However, if you raise preflop and all opponents fold you will pay no rake. In NLHE this leads to 3betting becoming more attractive than flat calling a raise because you have the chance to win the pot without paying rake if all players fold. I'm not a PLO player but what I can tell you is that in PLO there is a lot less folding to 3bets compared to NLHE due to hands generally retaining their equity better with four cards. So I assume this second effect should be much weaker at PLO because there is not much folding going on and maybe it's not even worth deviating your strategy but theoretically there should be an incentive to 3bet marginally more.

Tyler Forrester (Elite coach) has dedicated two videos to rake and its impact on strategies where he noticed that postflop strategies don't really change considerably only due to rake being a bit higher. If you have a chance I can suggest you to check those out even though it's not PLO specific.
Rake Effects at Small Stakes - Tyler Forrester (Elite)
Rake Simulation and Live Play - Tyler Forrester (Elite)

If you're interested also take a look at videos that help the shift from other games to PLO There is the learning path for PLO and then the tab -> Transitioning from NLHE to PLO providing a selection of videos on this topic. For instance, PLO essential coach Nick Johnson recorded a complete series for transitioning players and starts with preflop play which should be most interesting if you're thinking about rake:
Transitioning from NLHE to PLO (Part 1: Preflop Play) - Nick Johnson (Essential)

Of course any further advice from PLO players to this thread would be highly appreciated.

I wasn't paying nearly enough attention to the rake in the games I played last year and I think that not tightening up appropriately was the single biggest contributor to my frustrations, results-wise.

And it's a very sneaky leak that I really only started fixing recently.

So, just try really hard to make sure you're not seeing too many flops. Because—if you're playing too loose—after rake, your showdown winnings are just going to be too flat for you to win overall (even with a decent W$SD).

Thanks soo much guys for the answers. The video help me a lot :)