I’d suggest that there are at least two factors at play here.
A different getting up time for events. Ideally I’d suggest getting the body into the right rhythm for at least a week before. When van Impe won the Tour, he changed his daily routine to French time for a month before the start. Establish a bedtime routine, stay away from screens,
Anxiety coming up to the event. Maybe being in a different bed if the event isn’t local. I’d suggest trying some relaxation techniques etc well before, to find out what could work for you. Personally, I use prescribed sleeping tablets, but again, try before an important event. For me, having everything for the morning packed or laid out helps me to relax. A tick sheet and a time- line for breakfast, pre- event drinks etc also works for me.