On Android 12 it's fairly straightforward once you've changed the setting.
Settings > Google > All Services > Settings for Google apps > Play Games > Sign-in account
For Dominations, change the setting to 'Ask each time'. Each time you open the game it'll ask which account you want to use
Training and Tactics Blessing times have reduced since the latest update. Previously they were 1 and 3 hours respectively, since the update this has reduced to 40 minutes for the Training Blessing and 2 hours for the Tactics Blessing.
This appears only to affect the blessings which are stored...