I appreciate efforts of those that aided me on my newtxtext, newtxmath problem. I have now updated my TeX distribution (MiKTeX) and now I was able to run the code as edited here which didn't initially run. Right now, I tried running a code with mtpro2 as follows and I got the error below.
\documentclass[a4paper, 11pt, openany, oneside]{book}
\usepackage{phfthm}
\usepackage{float}
\usepackage[T1]{fontenc}
\usepackage[lite]{mtpro2}
\usepackage{newtxtext,newtxmath}
\usepackage{amsmath}
\usepackage[dvipsnames]{xcolor}
\usepackage{tikz}
\usetikzlibrary{patterns}
\usepackage{venndiagram}
\usepackage{fancyhdr}
\usepackage{authblk}
\usepackage[inline]{enumitem}
\usepackage{multicol}
\usepackage[Glenn]{fncychap}
\usepackage{currency}
\usepackage{tasks}
\usepackage{longtable}
\usepackage{caption}
\usepackage{tabstackengine}
\usepackage{nicematrix}
\usepackage[urlcolor=blue, colorlinks=true, linkcolor=blue, citecolor=red]{hyperref}
\DeclareMathAlphabet{\mathcal}{OMS}{cmsy}{m}{n}
%%% theorems
\theoremstyle{definition}
\newtheorem{ex}{Example}
\newtheorem*{sol}{Solution}
%%% commands
\newcommand{\lra}{\Longrightarrow}
\newcommand{\llra}{\Longleftrightarrow}
\newcommand{\call}{\mathcal}
\newcommand{\inl}{\textup}
\newcommand{\sbs}{\subset}
\makeatletter
\newcommand*{\rom}[1]{\expandafter@slowromancap\romannumeral #1@}
\makeatother
%%% metadata
\title{Title}
\author{Author}
\begin{document}
Body
\end{document}
From the logfile:
Couldn't open `mt2e.cfg'
[…]
miktex-maketfm: major issue: User/administrator updates are out-of-sync.
! Font \MTEXA@=mt2exa at 10.95pt not loadable: Metric (TFM) file not found.
<to be read again>
\font
l.130 \font
\MTXL@=mt2xl at \the\dimen@
?
newtxandmtpro2? – egreg Mar 27 '22 at 08:21