I have heard that Cuenca is full of expats for sure. Manizales I havent heard of there being a huge expat community, but I know a lot do live in Armenia, and Pereira, which are two smaller towns outside Manizales.
I love Manizales.. but if you are looking for cooler weather, and don´t mind the altitude check out Tunja... I loved that city. I did a video on it, to give you an idea of what it is like.
https://youtu.be/MGy9yzQRH5o?si=EQT21IYLMJd6GsE6
Also if you move to Colombia and choose any smaller area, you will not run into many other Americans.
The other day I met my first one here where I live and haven´t seen her again!