So I just checked:
1) No caching in the server. I use wp-rocket, but it’s already setup to exclude:
2) The max_execution_time is already at 3600, do you think I should increase it even more?
By the way, I’m using PHP 7.0. Would it help if I upgrade to 7.1? Last time I had tried 7.1, there were some problems with Event Espresso.