I had the same symptom due to psutil not being found during YoLink installation. The solution was to connect using SSH (using PuTTY for example) and installing psutil:
sudo pkg install py39-psutil
This is the thread about this:
I was able to get YoLink installed and it appears to be working great! Temp/humidity sensors and leak sensors are all reporting normally.
The problem I was experiencing during installation was a failure when automatically compiling psutil after the PG3 YoLink node server couldn't find psutil 5.9.2.
I'm not sure if this is a workaround in need of a permanent solution, or a solution that should be documented. Anyway, the solution was to install the psutil package:
sudo pkg install py39-psutil
