On Fri, 05 Mar 2021 14:34:15 +0100 Lars Ingebrigtsen <larsi@gnus.org> wrote:

> adam@faryna.io writes:
>
>> I did but nothing new shows up.
>>
>> Also while Emacs is running it brings to the front the *Warning*
>> buffer with this calendar errors, as it probably continue try to
>> initialize it.
>
> Very odd.  Does anybody else have any suggestions for debugging this?

You can put this in your init file:

(setq calendar-debug-sexp t)

I made an init file consisting of the sexps in the OP (except for the
ones involving japanese-holidays, since I don't have that package),
added the above for debugging, started Emacs, did `M-x calendar', typed
`h' on a date in the Calendar buffer, and got this backtrace: