If you did not know this before, welcome to being woke.
The way we do them is of course even MORE time-consuming and resource-intensive because we re-create connections to attendees in meetings. Because of the way EWS works this means more time and effort.
UNLESS... you consider that historical events do not really need to be fully-recreated.
Oh... please tell me more!
YES! If you (say) do a full-state migration take data from (say) a month back and into the future as full-state.
The key is the Calendar Selection Dates in your Configuration.
Your usual insertion settings for live meetings is this: Do that for say (Today-30 days) into the Future at 2039.
For an archive / historical insertion: Do this for (Whenever your earliest necessary date is) to (Today-30) Date.
Make sure you use a different