Right now, ubports does not support very many smartwatches. Pretty much only asteroid os watches through the Telescope app.
Amazfish is a sailfish os app that connects amazfit, mi band, and pinetime watches to your phone. The source is here: https://github.com/piggz/harbour-amazfish
According to https://github.com/piggz/harbour-amazfish/issues/119 all that it needs is a ubports specific ui since the daemon is separate. Would someone be willing to port it to ubports?