Sometimes events are not loading

Hello,

i have mutiple events ( about 8000 ) and sometimes my events are not loading. If i open the page where the calendar is shown the events for the current month are displaying but when i click the button to switch to the next month, the loading-animation stops and no events are displayed.
If i enable WP_DEBUG_LOG this issue occurs everytime. If its disabled, the issue occurs only sometimes. Do you have any idea how to fix this or to clean up my wordpress to prevent those (probably) ajax request fails? Or do you think that 8000 events are too many events?

Thanks for help!

https://ww.wp.xz.cn/plugins/event-organiser/