There are lots of calendar plugins in the repository. Do any present calendars as continuous? IDK, you’d need to investigate further for yourself. Most calendar plugins use them to manage events or bookings and the like. You should be able to ignore that aspect if you don’t need it and just focus on the calendar presentation.
If those all are not suitable for any reason, unless someone else can offer a specific reference, you’re possibly looking at something that needs to be bespoke developed. I believe there are freely available software calendar algorithms that let you generate correct calendar data for any time span. If the algorithm’s language is not JS or PHP, it would need to be translated into a WP compatible form. Since the algorithm is mainly maths, you don’t need to know the source language all that well to translate.
As usual, the biggest challenge in a bespoke plugin is developing a nice presentable UI from the derived data.
