I don't need to imagine. This is how government and bank websites work in Japan. It's maddening how frequently online services are closed in the evening and weekends.

Example: the government e-tax service's operating hours schedule

https://www.e-tax.nta.go.jp/info_center/index.htm

There is a full week of maintenance this month, and it's unavailable after midnight on Mondays and Sundays until 8:30am.