`nicematrix` NiceTabularX alignment

Question

I am trying to save horizontal space in a nicematrix NiceTabularX table as the report my table is going in has a page limit (the table is half a page long). I desire using nicematrix as I use tikz, \tabularnote{} and a coloured header which doesn't bleed in my main table so would prefer to use this. By way of an image, this is how my MWE table looked initially (colour added manually):

I have controlled the red distance so it is flush to the left margin by using \begin{NiceTabularX}{\textwidth}{@{}c!{}X} (pg. 7 of the nicematrix documentation) but I do not know how to control the distance of the blue line. I want there to be some space but also want to control as I have pruned my table but reducing the space could perhaps save me a line or two which is desirable.

Using {\textwidth}{@{}c!{}@{}l!{}} produced this so I feel that I need the X column:

Does anyone know how I can control the distance between the first and second columns in a NiceTabularX table whilst allowing line breaks please? I cannot claim too much experience with tables so apologies if this is basic or asked before, I checked the NiceTabularX questions on here.

How it currently looks:

MWE:

\documentclass{book}
\usepackage{nicematrix}
\usepackage{booktabs}
\usepackage{lipsum}
\begin{document}
\begin{table}
\footnotesize
\begin{NiceTabularX}{\textwidth}{@{}c!{}X}
\toprule
\textbf{Year} & \textbf{Important milestones or key achievements in de novo enzyme design}\ \midrule
1983-84 & \lipsum[1][1-3] \ \addlinespace[0.1em]
1994    & \lipsum[1][1-3] \ \addlinespace[0.1em]
1995    & \lipsum[1][1-3] \ \addlinespace[0.1em]
2000-04 & \lipsum[1][1-3] \ \addlinespace[0.1em]
2010-14 & \lipsum[1][1-3] \ \addlinespace[0.1em]
\bottomrule
\end{NiceTabularX}
\end{table}
\end{document}

Answer 1

You don't seem to be making effective use of the various easily available spacing options. For instance, you could insert @{} at both ends of the tabular-like environment in order to eliminate any unwanted whitespace padding at the edges of the tabular-like environment.

The amount of intercolumn whitespace is given by 2\tabcolsep. To generate less of this whitespace, you can either set a smaller value for \tabcolsep (its default value is 6pt in most document classes), or you can state directly how much whitespace you're willing to allow between columns 1 and 2 -- by writing, say, @{\hspace{4pt}} if 4pt is the desired amount of whitespace.

I'm not sure if your real document makes further use of the machinery provided by the nicematrix package. As the following screenshot demonstrates, there's no difference between using a NiceTabularX environment or just a plain old tabularx environment, for the code you've provided.

Oh, please do use -- rather than - to generate typographic en-dashes between year groups.

\documentclass{book}
\usepackage{tabularx,nicematrix}
\usepackage{booktabs,lipsum}
\newcommand\blob{%
  \toprule
  \textbf{Year} & 
  \textbf{Important milestones or key achievements in de novo enzyme design}\ 
  \midrule
  1983--84 & \lipsum[1][1-3] \ \addlinespace[0.1em]
  1994     & \lipsum[1][1-3] \ \addlinespace[0.1em]
  1995     & \lipsum[1][1-3] \ \addlinespace[0.1em]
  2000--04 & \lipsum[1][1-3] \ \addlinespace[0.1em]
  2010--14 & \lipsum[1][1-3] \ \addlinespace[0.1em]
  \bottomrule}
\begin{document}
\begin{table}
\footnotesize
\begin{NiceTabularX}{\textwidth}{@{} l @{\hspace{4pt}} X @{}}
\blob
\end{NiceTabularX}
\bigskip
\begin{tabularx}{\textwidth}{@{} l @{\hspace{4pt}} X @{}}
\blob
\end{tabularx}
\end{table}
\end{document}

Answer 2

Well, you stres that solution should consider nicematrix package, but anyway use tabularray is a good alternative (which need to be compiled only ones):

\documentclass{book}
\usepackage{tabularray}
\UseTblrLibrary{booktabs}
\usepackage{lipsum}
\begin{document}
    \begin{table}
    \footnotesize
\begin{tblr}{colsep  = 4pt, % or desired amount
             colspec = {@{} l X[j] @{}},
             row{1}  = {font=\bfseries}
             }
    \toprule
Year    & Important milestones or key achievements in de novo enzyme design \
    \midrule
1983-84 & \lipsum[1][1-3] \
1994    & \lipsum[1][1-3] \
1995    & \lipsum[1][1-3] \
2000-04 & \lipsum[1][1-3] \
2010-14 & \lipsum[1][1-3] \
    \bottomrule
\end{tblr}
    \end{table}
\end{document}