Good evening Sam and welcome to the Events Calendar Support forum!
Thank you for reaching out to us with your question.
Unfortunately at the current time, the recurring event functionality does not allow to target specific dates that do not follow a specific pattern (e.g.: every 1st Monday of the month). But that would be a great feature.
In fact, you can suggest it or cast your vote on other features in our User Voice forum.
For now, your best bet would be to create repeating rules to match your target dates and a lot of exclusions to remove the unwanted dates that are generated as a result of those rules.
I wish I had a better answer, but that’s the only one I have for now.
Let me know if you want me to walk you through what that would look like or if you have any other questions for me.
Have a great day!
Geoff B.