Short answer .... Maybe. Long answer its possible. They install a conversion server along with TikTok, now, this isn't really all that dangerous but depending on the device there are implications. For Android, they were making subsystem calls so they could scan your contacts, read your files, potentially monitor network traffic, etc. However, on iOS devices with the latest security reveal from Apple, they could technically have grabbed anything you copied on your phone and this could also have been used to transfer data from that block to anywhere they wanted.
Now, you get some code from homebase, run it on the user's network and start port scanning other networks and listening to their data streams in the hopes you'll catch something there too. It really is quite a complex hack if I am being honest.