If TikTok in the US is spun off as a separate entity, how hard would it be for the current company to put in a back door to still access the data.

Data is expensive, and tiktok collects a lot
- Nothing is too expensive for a government my friend.

No need. Most apps already collect a ton of data, and is sold to anyone who asks nicely. Which company owns a service won't change that one bit.

The whole thing is election-year performative bullshit, while your data isn't one iota safer.

You correctly answered OP's question. But the question was irrelevant to begin with. The ban on TikTok has nothing to do with data collection. It's about controlling potential sources of foreign interference: controlling what is said or how platforms (pick and choose what to) broadcast what people are saying.
Ehhhhh idk about that, reverse engineering efforts have found that it collects a lot more than other apps. Lots of seemingly unnecessary stuff.
Also, there's the whole thing with it burrowing in your internal files whether you delete it or not so it can continue collecting data after you uninstall, among with other suspicious (and strangely sophisticated) behaviors.
Also, it's bipartisan so I don't see where the "performative bullshit" is, it's genuinely a really well written virus that everyone willingly has installed on their phones, controlled by a country who's actively an openly a surveillance state. Not to mention the mental health implications; they don't even let their own citizens use it for more than an hour a day.

They’d just buy the data like they do every other social media company.

This is performative bullshit. If they really really cared, they’d ban companies from collecting it in the first place.

Exactly.
No need for conspiracy or back doors. The only downside is ByteDance having to pay for data that they got as part of running the platform. Heck, they can probably even find a way to run control through shell corps or other means like being a big shareholder of some intermediate investment and nothing will change.
This is more about pro-palenstinan content on TikTok than data.
- This issue far predates the current outbreak of war in Gaza. It’s also about the CCP being able to directly feed propaganda to Americans.
  (Only American companies are allowed.)
  The national security argument is actually valid, but banning TikTok doesn’t resolve the core problem: that the data exists and is being sold everyday to basically anyone that can afford it, including the CCP, Russia, North Korea, Iran, ISIS, other people like ISIs, Domestic terrorists that pretend they’re not like ISOS, and dozens of organized crime groups.
Their old asses don't know that and no amount of explaining will help them understand.

No backdoor necessary. They own the data. It's theirs to do what they want with.

All online services have access to everything done on their system. Unless it uses End to End Zero Knowledge Encryption.

But this isn't about collecting data. Its about China shaping the algorithm to shape American public opinion. As NYT discovered they are in fact doing already.

I just wish they would address the US corporations doing the exact same thing, using algorithms to shape American public opinion.
It's just hypocritical for them to go after TikTok for doing it, specifically, when Meta and Google are doing the same thing, and have been doing so for longer.
If they really cared about this negatively affecting US public opinion, they would make a blanket law about algorithm shaping and go after any corpo that breaks it. Sadly, that won't happen, because the US corpos are in our politicians pockets.
- Has anyone actually shown that any American social media is suppressing specific topics? There are plenty of accusations and anecdotes, but I haven't found any statically significant data.
  They certainly tune for engagement, which tends to cater to people's darker impulses. While that's harmful generally, it's very different than deliberately suppressing specific viewpoints.

Super easy, barely an inconvience

I'm not sure but I think the issue is not so much what data is available and more how the data is served to users via the algorithm.

Imagine if it's served in a way that intentionally makes users want to vote against their own interests.

That said, I have no idea what I'm talking about.

Trivial, it might actually be harder not too.

Terms of Sale:

Buyer agrees to sell user data to TT DataVacuum, LLC

Buyer agrees to install For You page algorithm updates per the requirements of TT DataVacuum, LLC on a quarterly basis.

Btw our lawyers are still setting up our new LLC with nominee directors. Dont worry, totally American.

It's unlikely because of how scrutinized the code will be once it's sold, but not impossible. It'll be caught eventually if it is backdoored, though.

Not hard at all.

A code audit?

Data access is just one issue. Executing CCP propaganda policy (shadowbanning topics critical of the CCP and amplifying topics that divide/destabilize western democracies) is at least as worrisome.