Will SIM Free iPhones work if used initially out of UK?

Hi there, (first time asking in the community)

I am currently waiting on a new SIM Free iPhone 15 Pro Max, the device will be primarily used out of UK and possibly first set up with a SIM card in Africa (where I live).

Will the phone be blocked for use in other countries till it is activated on a UK network or it will be free to use? (I had an android in the past that required it to be on a call from a UK carrier for at least 10 minutes, is this the case with Apple?)