just monitor. I am unsure about the region lock thing, but it is present all over the internet and even some carousellers trying to sell OnePlus phones, and it has region lock (they sell it off because the phone is basically unusable). from what I know, it doesn't happen immediately, but only after some time. phone will start behaving weirdly like cannot make phone calls, auto brightness goes haywire, fingerprint sensor not working etc...
I am just suggesting to go with local set, but it is up to individual whether to take the risk or not. I do not want to bear the responsibility to ask someone to buy export set and they got the region lock issue. seller can claim there is no region lock, as they want sale. if got issue, are they going to do a refund to u on the phone?