Using my Xfinity LOCKED iphone 15, with an esim?

My new iphone 15 is locked by xfinity. When I travel overseas I just heard there is an alternative to their three choices. Xfinity gave me the option of paying off my phone in order to unlock it, or paying them $10/day for all services, or paying by the minute and text for texts, calls and data.

i just heard that we can work around the above quite simply and cheaply by TURNING OFF my cellular service, and then buying a cheap esim, that provides data, text, and phone service, albeit with a new foreign phone number.

Does this sound right, that with a click in cellular settings, we can use a locked phone on a foreign networks esim card?

thanks