The Pocophone F1 is not compatible with any US carriers. From the GSMArena specs page:
While it supports 1900MHz for text messages, it does not support any of the LTE bands for VoLTE phone calls or data on any US network.
For reference, Ting GSM uses LTE Band 2, Band 4, Band 12, Band 66 and Band 71. The Pocophone doesn't support any of them. The fact that it's missing Band 4 also means it won't work on AT&T or Verizon (or any of their MVNOs) and the lack of Band 25 means it won't work on Sprint, either.
In the US, the Pocophone F1 isn't useful for any phone things. If you need help picking something else, I'd suggest submitting a request to our personal shoppers. They'll be sure to get you a few options that are Ting compatible.