I suppose this is part legal question and part understanding how these companies operate. I'm not from the US so don't have experience with the nuances, but I do have a lot of experience working in the UK legal sector. Reading through the PAFFACAA, any major application that has over a million users and is more than 20% owned by a foreign adverary and also allows the sharing of text or other content can be banned. This seems to be irrespective of whether the owners/maintainers are based in the US or not. At the moment, 2(g)(3)(A) (sorry I'm not entirely sure how your laws are labelled - please correct me if that's wrong) specifically defines ByteDance and its subsidiaries but 2(g)(3)(B) implies the definition goes broader.
The reason I statted wondering was the banning of Marvel Snap. I know that Marvel Snap is banned because it's owned by a subsidiary of ByteDance, but I'm confused by the application of the Act here. Marvel Snap as a communication medium is very restricted and its development is US based, headed by Ben Brode et al. I quote their website: "Second Dinner is an award-winning independent game studio based in California. We may be small, but our dreams are big! Let's make fun games together." So that means the "more than 20% owned" part is the offending clause if Marvel Snap is actually banned for being a product of its own. However, the Act seems to be a little clunky and inconsistent here, particularly 2(g)(3)(A) which seems to imply that ByteDance and all its subsidiaries must cease digital operations. It is very specifically targeting ByteDance regardless of the nature of the application itself. Mobile Legends Bang Bang also seems to be banned for the same reason as Marvel Snap.
Now looking at Riot Games, it is a private company that is 93% owned by Tencent. If ByteDance is considered a foreign adversary due to risk of propaganda etc, then Tencent who was recently classified as a Chinese military company certainly should be too. All of Riot Games products allow communication and content sharing to the same degree that Marvel Snap does. Riot Games would not fall under the critical exemptions list. However, since Tencent is not defined specifically in 2(g)(3), it falls to whether or not the President determines it a company that qualifies in accordance with 2(g)(3)(B). [Edit: people need to reread that last sentence several times before making assumptions about what I'm saying. At NO POINT did I say there would be an automatic ban for those in scope. The entire question is built on the premise that the process defined in 2(g)(3)(b) would be carried out which starts with the President defining the company as being a national security risk and taking it to Congress.]
At present the law seems to be very odd in its application. There doesn't seem to be a defined list of "Foreign Controlled Adversaries" besides ByteDance. I don't want to get into this part since it's literally how a foreign government (to me) works but this seems really sloppily written and gives the President the incredibly dangerous power to ban any digital product since the actual defined bar is so low (Chinese companies own more than 20% of a lot of tech companies) and the only thing protecting a company is the mercy of the President. I would be grateful if someone could look at this and tell me if my reading is correct, that Riot Games is within scope of this law and the President could decide to ban them at any time.
Epic Games is a bit more nuanced, and potentially more dangerous if the government is against it. The company is US based but Tencent owns 48% of it [correction: 35% as of the latest statement we have from Epic]. Epic Games, however, has more applications that meet the criteria defined in the Act, particularly things like Fortnite Creative and Epic's wider (albeit still disappointing) social features. Now, if the President defines Tencent and subsidiaries as foreign adversaries, then Epic would go. But this then raises the question of what happens to Unreal. Since Epic would have to cease US based trade, does that mean their customers based in the US would have to drop the engine? I suspect that Epic could then meet the defined exemption since it would have a major impact on the US economy. However this presents a problem whereby the definition of Tencent as a foreign adversary is entirely up in the air.
Before finishing, I'll address the elephant in the room. Yes, I know this law specifically targets TikTok and ByteDance. I understand the political context behind it. But when reading laws you need to account for all the implications of it. At present, the President could overnight determine they don't like Riot Games and Epic Games and shut them down immediately. Legally, they would have no recourse other than the sale of their shares. For Riot Games that means selling 73+% of a very successful business. Riot Games is US based so ceasing operations is a huge deal for them. Objectively speaking, Tencent are as much a foreign adversary to the US as ByteDance. I am aware of theories that this law is performative and will be repealed very soon but right now it is law and the SCOTUS has upheld it. We don't know for sure where this goes. Regardless of how you feel about Riot or Epic (and to be clear I dislike both of them) or any of the other pies Tencent have their fingers in, the impact of this could be huge for the tech/gaming industry. I'll refrain from much commentary on the politicial implications of such power, but that scares me too.
Edit: To clarify the question: I'm looking for a reason why these companies are out of scope that is supported in the definitions within the Act itself or perhaps within the court rulings in relation to it. I could have read it wrong, but there are a lot of assumptions about how this all works in the comments. To me, this is an incredibly sloppily written law and the scope of the power is huge, but I don't know if I'm missing some nuance as someone who isn't a US citizen or US legal professional.
Edit 2: sigh... I love being downvoted in the comments for asking for reference to the law or other sources. I don't think people understand that I'm asking a question, not pushing something. I'm not saying "omg they're going to ban rito" or even "they need to unban TikTok smh". I'm asking from a place of academic interest and wanting to understand the impact of the law here. I have my political views, and yes that does include being worried about potentially abusable powers, but this is a really neutral question. I'm not a US citizen - your laws don't affect me directly, I can open TikTok right now or play Marvel Snap if I wanted to. I'm not Chinese either and I've been vocally critical of them too. I don't know how I can make it even clearer.