As far as I was aware you don't have a constitutional right to a product or service.
The Constitution doesn't grant you any rights. You were born with them by virtue of being a human being. What the Constitution does is grant the Federal Government certain powers and responsibilities. This is a longstanding concept in our legal tradition, predating the Constitution, and it's codified in the 9th and 10th Amendments.
That said, the Federal Government might be able to "ban" TikTok under interstate and foreign commerce/relations, and/or national defense authorities. If they did this and it survived the inevitable legal challenges, the App would disappear from Apple and Android's app stores, and American companies and consumers would be prohibited from buying advertisements on the platform or otherwise sending TikTok money. Problem with that, if ByteDance were so inclined, they could continue to make the platform available via a webpage. There's no process under American law that would authorize any level of Government to block access to a webpage. The Government can't even block hacking attempts from abroad that target critical infrastructure and don't think for a second NSA wouldn't be capable of doing it if tasked with the mission and authority.
The only path I could see to outright blocking TikTok would be under POTUS'es war powers. Check out Lincoln for examples of the good, bad, and ugly use of Presidential War Power. This ain't possible unless we find ourselves in a shooting war with the PRC. At that point, I'm worried about a lot more than TikTok.
If you've seen any of my comments I am no fan of the PRC and Winnie the Pooh, or for that matter, social media. Despite that, I strenuously object to the dangerous idea that we can or should ban TikTok. The biggest danger of TikTok is the CCP putting its thumb on the algorithmic scale to facilitate the spread of misinformation. Facebook and Twitter are already doing this! We're cool beaming disinformation directly into the lizard brains of American citizens so long as it's an American corporation reaping the profits? Yeah, that makes sense. You fix this problem by helping people learn how to think critically and spot disinformation. Not by trying to ban shit.
P.S., I do not see how a State Government has any authority whatsoever to ban TikTok. This is unquestionably interstate and foreign commerce. The Grandstanding idiots in the Montana State Legislature are probably too stupid to know this but their legal advisors and the serious legislators in the Legislature surely do....