As you mentioned, many other FPS shooters have attempted to mimic Apex's ping system, and Battlefield had a (much more primitive) ping system years before Apex even came out.
But there is one particular reason (that OP and many others often miss) why Apex's ping system is still MILES ahead of any other game: every ping is voice lined. Literally anything that you ping, from the obvious stuff like enemies/ammo/weapons, to the mundane stuff such as an open door/lava/zip lines, is fully voiced by every character in the game.
There's so much nuance to the system. If you ping ammo in Apex, your character will specify that it is light/heavy/shotgun etc. ammo. In other games, at best there will be a slightly different ping sound to indicate ammo, but you will still need to read text on the screen somewhere to see what type it is.
It's really easy to overlook but difficult to overstate just how important the voicelines are. When you ping in any other game, usually a marker Is placed and a generic audio cue is played. Sometimes there will be a label or text somewhere in the UI to provide further details for what the ping is for. This lazier approach is certainly cheaper & easier to implement, but has a multitude of drawbacks that aren't immediately obvious.
In the heat of battle, the voice lined pings in Apex minimizes the need to divert attention to see what your teammates are pinging. For example, let's say your team is losing a fight, and you want to ping a zip line that could be used for escape. In Apex your character will say something like "zip line here", which immediately conveys your intentions. In other games, your teammates might hear the ping sound, but they will have to waste time finding the location of the marker, or reading the text that informs them of the zip line. In the middle of a fight, that extra second or two can easily cost you the victory.
Also, because squads in Apex can't have duplicate characters, the unique voice lines allow you to immediately determine which teammate is pinging, even without looking at the screen.
It's genuinely impressive how much Respawn has (and continues to) invest into their ping system - it certainly can't be cheap to hire and retain dozens of voice actors for years to keep it running. Keep in mind that new voice lines (for every single character) have to be added each season, either to compliment newly added weapons/maps/features, or to incrementally improve quality of life. For example, one great addition from last season was the ability to ping (and have your character call out) an enemy that's being revived.
The end result of Respawn's efforts is that Apex has a much smaller handicap to play without a mic, and virtually every player in the game actively uses the system, all the time. Whereas I've noticed in Battlefield, Warzone, and Fortnite, players will mostly only ping enemies (and not much else).