Yes, you can, but we don’t recommend it.
TikTok and Instagram require specific different setups to get consistent results (account creation methods, device setup, network/SIM setup, etc.).
What we recommend:
Use an iPhone dedicated to TikTok
Use another iPhone for Instagram / Threads / Facebook / X (Twitter)
If you still want to combine them, it’s possible, just that results may be less consistent.
Read more about each setup here: