I am curious how high it is compared to holdem?
Thanks. I found a chart that better goes into how much rake is payed in general. It seems that all the sites are making double or more off omaha in general per hand off rake making omaha way harder to have a decent winrate. Omaha players relies more on rakeback than holdem for sure.

These old charts list dealt 'rake', i.e. the total rake collected from the table, divided by the number of players dealt in. The real - attributed - rake (in pots won by a player; weighted contributed 'rake', on which VPPs are based, is usually very close but has smaller fluctuations, so VPPs are accrued quite steadily) is about 18/14/9 bb/100 for an average reg at PLO25/50/100 (the looser the player, the more rake s/he pays; recreationals suffer the most, paying up to twice more rake than regs).
This is because in PLO the average pot is bigger, it's more aggressive and looser than holdem.
So I don't think you pay more rake.
the rake is less than holdem at the micros, after that, the rake is same for holdem and omaha.