score:3
Baptists are by definition very independent. Each congregation sets its own beliefs, processes and celebrations, even if they belong to a larger denominational organization.
In general though Baptists celebrate very few festivals, typically limited to Christmas and Easter. Ascension day is not one, and is certainly not a "major festival". The situation may be different in places where Ascension Day is a public holiday, but given the number of Baptists who do not hold a church service on Christmas day I suspect not.