Hi,
Would recommend to make full use of the day night cycle. Where day, enemy is easier and also good for harvesting the environment. When night, enemy evolved to pestilence making it harder but the reward also better.
Making it like “Dying Light” where enemy is harder at night but the rewards is better. Or Elden ring, night only appear black knight at certain time. Or random field bosses pop up but the rewards definitely need to be worth it. Unpredictable enemy is always the best.
Cheers