For
\sup_{\varrho_{i}, \forall i}
What should I change such that I have this subscript exactly under sup?
To have subscripts below \sup at in-line math gives ugly result:
so I strongly discourage to use it on such a way. At display math is different story. There this is standard way to write \sup:
documentclass{article}
\usepackage{amsmath} % not needed for reproducing your problem
\usepackage{lipsum}
\begin{document}
I get $\sup\limits_{\varrho_{i}, \forall i}$ \lipsum[11]
\begin{equation}
\sup\limits_{\varrho_{i}, \forall i}
\end{equation}
\end{document}
$\sup...$, then use$\displaystyle\sup...$instead. – Werner Jan 27 '22 at 23:04\sup\limits_{\varrho_i,\forall i}but you'll spoil the distances between base lines. – egreg Jan 27 '22 at 23:07