Capitalizing first character of \today independently of the language

Question

I'm writing a document class that uses the datetime2 package to write a month-year date in the title of the document. Here is a MWE:

\begin{filecontents}[overwrite]{customclass.cls}
    \NeedsTeXFormat{LaTeX2e}
    \ProvidesClass{customclass}[2014/12/16 Custom class]
    \LoadClassWithOptions{article}
    \RequirePackage{babel}
    \RequirePackage[useregional]{datetime2}
    \DTMlangsetup*{showdayofmonth=false}
    \renewcommand{\maketitle}[0]{\today}
\end{filecontents}

\documentclass[<language>]{customclass}

\begin{document}
\maketitle
\end{document}

I have run into the problem that many languages don't capitalize month names, whereas the desired behavior would be to capitalize them since it is a title (e.g. "Marzo de 2022" instead of "marzo de 2022").

I have tried using \expandafter\MakeUppercase and also the mfirstuc package as explained here, but none of those work (I assume it's because the \today command is pretty complex so it's not easy to expand?). I also cannot hard-code month names because I expect this class to work independently of language, and because I regularly use four languages to typeset documents (French, Italian, Spanish and English, three of which display this issue).

I would love a bit of help with this!

Answer 1

By creating a new style (e.g. mydate) which display month date with a capital (with \DTMMonthname) you obtain you target. We need also the package datetime-calc which convert the numeric value of the current month date to the month in letters.

In \DTMdisplaydate, the second parameter is the number of the month (3 for March), and the first is the year.

Edit: Bug fix provided because in italian language, the datetime2 package don't provide uppercased month names.

Edit 2: I have also managed the spanish case, replacing the "Month Year" output by "Month de Year" (e.g. Marzo de 2023).

\begin{filecontents}[overwrite]{customclass.cls}
    \NeedsTeXFormat{LaTeX2e}
    \ProvidesClass{customclass}[2014/12/16 Custom class]
    \LoadClassWithOptions{article}
    \RequirePackage{babel}
    \RequirePackage{datetime2}
    \RequirePackage{datetime2-calc}
    %% Correction of a bug: in italian, Uppercase months are missing in datetime2
\newcommand*{\DTMitalianMonthname}[1]{%
 \ifcase#1
 \or
 Gennaio%
 \or
 Febbraio%
 \or
 Marzo%
 \or
 Aprile%
 \or
 Maggio%
 \or
 Giugno%
 \or
 Luglio%
 \or
 Agosto%
 \or
 Settembre%
 \or
 Ottobre%
 \or
 Novembre%
 \or
 Dicembre%
 \fi
 }
%% End of bug correction
    \DTMnewdatestyle{mydate}{%
    \renewcommand*{\DTMdisplaydate}[4]{%
    \DTMMonthname{##2} \iflanguage{spanish}{de }{}##1%
    }}
    \DTMsetdatestyle{mydate}
    \renewcommand{\maketitle}{\today}
\end{filecontents}

\documentclass[french]{customclass}

\begin{document}
\maketitle
\end{document}

With \documentclass[spanish]{customclass}:

With \documentclass[english]{customclass}: