Good evening Nick and welcome to the Events Calendar Support forum!
Thank you for reaching out to us.
We are sorry to hear about
I would love to help you with this topic.
First off, I am not sure if this is accurate, but based on your system info, it looks like your PHP memory limit is set to memory_limit = -1 .
I would recommend checking into that.
Secondly, I would recommend trying a different Events Template setting under Events -> Settings -> Display to see if that helps.
Thirdly, try to deactivate any CSS, Javascript or HTML minification in your caching plugin.
Finally, Try temporarily reverting back to a default WordPress theme such as twenty-sixteen to see if the issue persists (with a “Maintenance mode plugin active”).
Let me know how that goes.
Best regards,
Geoff B.