That’s just plane old wrong. view: yes will turn the panel into a separate tab at the top of the Overview. view: no will keep it in the format you want. see documentation:
You are getting a config error because you are using capitals when you shouldn’t be:
This is the correct config format:
group:
main_weather: # <--- CANT USE UPPER CASE
name: Tempo
entities:
- sensor.pws_weather_1d_metric
- sensor.pws_temp_high_1d_c
- sensor.pws_temp_c
- sensor.pws_temp_low_1d_c
- sensor.pws_precip_today_metric
- sensor.pws_feelslike_c