I have recently downloaded a font from https://www.dafont.com, which, when I call it into my document, requires the fontspec package and compilation with lualatex. This has caused several problems, most of which (though not all), I have been able to take care of.
I don't know if this is possible, but I am trying to find a way to call in the aforesaid font into my document without using fontspec.
Consider the following code:
\documentclass{book}
\ifdefined\directlua
\usepackage{fontspec}
\else
\usepackage[T1]{fontenc}
\usepackage[nomath]{lmodern}
\fi
\newfontfamily\CloisterBlack{CloisterBlack.ttf}
\begin{document}
\thispagestyle{empty}
\huge
\CloisterBlack{How to Use This Font without Fontspec?}
\end{document}
which when compiled with lualatex produces the following result:
I thought, perhaps, that I might replace \usepackage{fontspec} package with \usepackage[T1]{fontenc}\usepackage[nomath]{lmodern}, but when I compile the code with pdflatex I get an error.
QUESTION: How (if possible) may I invoke an externally downloaded font into a document and compile it without using fontspec? (I thought I found a way by replacing fontspec with unicode-math until I discovered that the latter package automatically loads the prior). Suggestions are welcome.
Thank you.

\newfontfamily\CloisterBlack{CloisterBlack.ttf}in the wrong place that has to be in the\ifdefined\directluabranch obviously it can not work if\newfontfamilyis not defined and pdflatex can not read ttf gonts. – David Carlisle Feb 28 '22 at 13:38T1-WGL4.encencoding that I used and use something more standard. – Steven B. Segletes Feb 28 '22 at 13:41lualatexis fine with me if I can use the font withoutfontspecasfontspechas caused problems. This is easy to solve?? I just thought ofpdflatexas a possible alternative because it does not handlefontspec. – DDS Feb 28 '22 at 13:45\bfseriesor\itshapeto do the right thing usingfontspecis the thing to do, if you are having issues with fontspec you probably have errors in your other code so the fix is probably not to avoid fontspec, but instead to fix whatever is causing the error. – David Carlisle Feb 28 '22 at 13:48lautexbranch using TexStudio? All my compiler choices right now have "latex" in their names. I'll keep looking as my text editor is, I'm sure, more archaic than yours. Thank you for your very helpful comment. – DDS Feb 28 '22 at 13:49\newfontfamilycommand into the\ifdefined\directluabranch of your code so that it is only used where it is defined. That is a fontspec command so just use it in the branch where you load fontspec. – David Carlisle Feb 28 '22 at 13:51\fmfamilyand have no argument, your use of\CloisterBlack{How to Use This Font without Fontspec?} ABCwill not generate an error but the braces do nothing useful and ABC will also be in the font. – David Carlisle Feb 28 '22 at 13:56