How to change the length of day and night?

For context, me and my friends are gonna start a minecraft server and for the spooky season, I'm putting in some simple horror datapacks. One thing that I want to try and do is change the length of the day and night cycle so that daytime lasts for the usual ten minutes but night lasts for 20 minutes. Is there anyway to achieve this using a datapack?
Also as a bonus question, are there any good horror datapacks you would suggest?