The forms of gatekeeping I've seen in FFXIV vary greatly. Most common in party finder for a raid where people would write in the comment what strat they are using. If they state the strat fine, you can look up a guide before joining. But often they would just put "usual party finder strat" How am I supposed to know what that is if I've never done that raid in party finder? And if you join and ask, they kick you. I don't have a raid group atm, would love to try one of the new raids but dreading the party finder because of this.
Another one is straight away against the T&C but there is no way to prove it. FFXIV doesn't have an official damage meter but there are 3rd party tools. If someone uploads logs from a fight you were in, you have results there against your character without your knowledge. People in party finder tend to check these and kick you from the group if they don't deem your performance in other duties good enough. But ofc you can't prove this so you can't report them either.
So by such means a lot of inexperienced people are denied a chance to get into raiding because they are forced to learn offline, by guides, get better in other content first and then show up for a raid progression already knowing what to do.
That's not how it should be and that's not how it is in Japan. Lets say a raid takes 5-10 mins to kill the boss. The duty instance lasts 2 hrs so you can wipe and try again and again without leaving. But groups don't have the patience for that.
I've been kicked from a party finder group before because I died 2x due to lag... And they said no mistakes allowed as it's a re-clear group for loot. I knew the fight, just my internet was having a bad day...