Calendar Datasource

Hello, I am using graphql datasource with neo4j as database and have days, weeks, months and years modelled as nodes.

I am looking for datasource that I can query to get:

for year 2021, all the months (1-12)
for month 12 in year 2021, all the days: 2021-12-01. - 2021-12-31
for year 2020, all the weeks (1-53)
for year 2020 and week 15, all the days (dates)

I need this for Query (Chained) Variables for my dashboards.

Is there anything already available?
If not, any suggestion what would be the easiest way to do that?

Precalculating everything and storing in a database (e.g mysql) is something I would like to avoid, if possible.

Thank you,