I doubt regulators or lawmakers that set these rules would look too kindly on a "free" dlc available at launch that adds in a feature that they are actively trying to regulate. While I don't have any ideas about the specific laws in question. I'd imagine there is something that can be done about companies that purposely circumvent the laws.
As I remember for at least ESRB (Europe outside Germany) DLCs have different age rating than the games, and there were cases were the DLC had a different rating than the main game.
ESRB is also an optional system (mandatory to publish on console) more like a suggestion, guide for mostly parents made by the gaming industry as self regulation. Not sure about how the German censorship/age rating system works as it seems to be something made by their government.
The industry knows very well that they are selling gambling to children and those easily exploitable by gambling mechanics without any supervision. Gambling laws are not here to abolish gambling, they are here to protect those who are either too young or have behavioral disabilities that increase they susceptibility towards impulsive spending.
I did work on F2P mobile and browser games and our company considered to include a feature where you were going to be able to earn real money.
The difference between gamling or not gambling was there, to earn money or not from a game where you paid real money. If the player can earn real money then the game falls under the gambling regulation and there are many strict regulations, government control and stuff there. So our company decided to avoid all this by not allowing people to earn money, in order to avoid to make any possible harm and to avoid a huge amount of paperwork required.
We researched about it a lot and according to the science, multiples studies regarding gambling and addiction and so on there's a big difference if you 'bet' real money or not. No serious study (including the ones they did use to decide the German change) was able to find a link lootboxes / gatcha mechanics to adiction or gambling related issues.
I did work there for many years, and had friends in other top mobile gaming companies who also took this very seriously, researched about it and found the same results: lootboxes / gatcha mechanics aren't gambling and doesn't have the issues that gambling/real money betting has, it only slightly increases the average amount of money people spends on games, or the time they spend playing it.
We -and myself personally, it was one of my tasks- contacted the players who spent a ton of money on our games, kept a personal contact with them and tracked their payments. A tiny percent of the people who spent money on our games, who at the same time were a tiny part of the total of players. And none of them became an addict or ruined their life, they mostly were rich bored people or normal players who spend a normal budget on gaming but happened to play a single game during hundreds/thousands of hours across several years, so spent all that budget for gaming there.
Other friends who did the same at other companies had a few cases of kids spending money from their parent's credit cards and solved the issue. And I'm talking about games that ranged from several dozens of millions of players to several hundreds of millions of players.
So no, both according to the studies from science and watching real world results with samples of hundreds of millions of players I can tell you that lootboxes / gatcha mechanics aren't gambling and don't cause the same issues that gambling causes.
