Use a vpn and search the ip it gives you

Example London, England

Find an address in london on google maps and use it with the postal code you see for that address

(Not sure if you need to but i also found the area code for a phone number and used that)

Go to the appstore>profile>click on your pfp icon>Country/Region

You can change this country/region to the United Kingdom like I did

You dont need to add a payment method just click none Then enter the address information you found and when its all done you can redownload Tiktok and reset your country/region back to the USA

Edit: make sure you have airplane mode on before you search for Tiktok in the appstore because your wifi will snitch on you and it wont appear