@Marilyn559
As @Mike-And-Jane0 mention, Discounts like early bird and last minute WILL stack on top of length of stay discounts (like weekly, monthly) if the booking period applies.
We don't use Early Bird or Last Minute for that reason, as they will stack on top of our weekly or monthly discounts if the reservation period applies:
Applying Multiple Discounts
https://www.airbnb.com/help/article/3421
Combining Discounts
https://www.airbnb.com/help/article/2061#section-heading-3-0