tableofcontents, chapter, etc. showing up in weird font

Question

PROBLEM SOLVED, SEE EDITS 2 AND 3.

so i have several files written in bulgarian that are set up to compile into one PDF however in the process of doing so, several errors popped up despite me compiling the files individually before with no issue whatsoever

first of all, when using \tableofcontents the file wounldn't build and texstudio would return errors like this instead

Command \CYRO unavailable in encoding OT1. ...C {\cyre }\IeC {\cyrm }\IeC {\cyri } }{7}{} problem is i'm not even using encoding OT1, but T2A and X2. removing talbeofcontents let the file build successfuly, however that bring us to my second issue

the font on tings like chapters, sections and certain symbols is replaced with this odd font

copying the text and pasting it somewhere else displays the text as saying "chapter 1" even though the text for everything should be in bulgarian

EDIT: upon further inspection, all latin characters seem to be affected, but none in cyrillic

EDIT 2: swapping the places of bulgarian and english in \usepackage corrected the font for the headers, as they display in bulgarian now and not garbled in any way. latin characters characters still appear to be messed- up though

EDIT 3: removing X2 from \usepackage[T2A, X2]{fontenc} fixed the problem with the garbled english font.

the packages i'm using are the following

\usepackage{amsmath,amssymb,latexsym}
\usepackage[T2A, X2]{fontenc}
\usepackage[cp1251]{inputenc}
\usepackage[bulgarian, english]{babel}
\usepackage{mathrsfs}
\usepackage{amsthm}
\usepackage{subcaption}
\usepackage{amsfonts}
\usepackage{graphicx}
\usepackage{epsfig}
\bibliographystyle{plain}
\usepackage[cp1251]{inputenc}
\usepackage[T2A, X2]{fontenc}
\usepackage[english,bulgarian]{babel}