I'm just going by what is written in the link I posted:
"Your pension will go up to the current rate if you return to live in the UK"
Makes no mention of moving to a third country having an agreement. I agree that may be the case, it's just not written down in that link, but I can't find any formal statement from the UK saying that it would be unfrozen by moving to, say, the Philippines. Everything I've read from an official source says you need to move back to the UK.
Note that UK residents of the EU, EEA and Switzerland only get the annual increase if they were already living there before the end of 2020, so moving to one of those countries definitely wouldn't thaw it.
Also, the last reciprocal agreement ever made was with Barbados in 1981. All governments since have said they will make no more, as it's "too expensive".