Georgian capital letter “Ⴒ” (“tar”) in pdfLaTeX

Would this alternative approach suffice?

\documentclass{article}
\begin{document}
\begingroup\ooalign{P\cr L}\endgroup
\end{document}

For completeness, there is a Georgian font package for pdflatex, see https://www.ctan.org/pkg/mxedruli. The Tar character is part of the Xucuri set, which can be accessed with \usepackage{xucuri}. The input is a set of ascii-based character combinations, with Ⴒ made by .T. Note that the character looks a bit different, like the difference between a serif and a sans serif font (although I don't know anything about Georgian, so maybe the difference is caused by something else entirely).

MWE:

\documentclass{article}
\usepackage{xucuri}
\usepackage{amsmath}
\def\tar{\raisebox{-1pt}{\text{\begin{xucr}.T\end{xucr}}}}
\begin{document}
$x=\tar(1)$
\end{document}

Result:

You would use the T8M/T8K encodings.

This requires the georgian CTAN package, which on TeX Live 2019 should be installed to texmf-local.

\documentclass{article}
\usepackage[T8M,T8K,T1]{fontenc}
\usepackage{amsmath}

\newcommand\mathTar{\mathord{\text{\usefont{T8M}{cmr}{m}{it}\symbol{"93}}}}

\begin{document}
\( \mathTar = P \cdot L \)
\end{document}

As you can see, the “Computer Modern Roman” Georgian font is really a closer match for DejaVu Serif. You might instead try the sans-serif cmgt font family, or something like this, which matches the “Dejavu Georgian” font family to DejaVu Serif:

\documentclass{article}
\usepackage[T8M,T8K,T1]{fontenc}
\usepackage[scaled=0.95]{DejaVuSerif}
\usepackage[italic]{mathastext}
\usepackage{amsmath}

\newcommand\mathTar{\mathord{\text{\usefont{T8M}{djg}{m}{it}\symbol{"93}}}}

\begin{document}
\( \mathTar = P \cdot L \)
\end{document}