I would like to have a progressive numbering of Theorems, Lemmas, Corollaries, Examples, Remarks, etc. within sections. While for equations I would like a numbering within chapters. Also, I would like the counter to be set to 0 when starting a new chapter. I would say that the main problem is that I use the package tcolorbox for theorems, corollaries, lemmas, etc., and amsthm for examples and remarks. Below you find the MWE I'd need.
\documentclass[x11names,two sides,12pt]{book}
\usepackage{changepage}
\usepackage[titles]{tocloft}
\renewcommand{\cftdot}{}
\renewcommand{\cftchapfont}{\normalsize \bf\scshape}
\renewcommand{\cftsecfont}{\normalsize}
\renewcommand{\cftsubsecfont}{\itshape}
\usepackage{geometry}
\geometry{
left=25mm,
right=25mm,
top=20mm,
bottom=20mm,
headheight=14pt
}
\usepackage{soul}
\usepackage{pgfkeys}
\usepackage{tikz,tikz-cd}
\usepackage{amsthm,amssymb,amsfonts,mathrsfs}
\usepackage[T1]{fontenc}
\usepackage[utf8]{inputenc}
\usepackage[english]{babel}
\usepackage[colorlinks = true,
linkcolor = blue,
filecolor=black,
urlcolor = black!40!cyan,
citecolor = blue,
anchorcolor = red!60!black,
pdfencoding=auto,
psdextra
]{hyperref}
\usepackage{tcolorbox}
\tcbuselibrary{theorems,breakable}
\usepackage[pagestyles, clearempty,explicit]{titlesec}
\usepackage[titles]{tocloft}
\usepackage[nottoc,numbib]{tocbibind}
\theoremstyle{definition}
\newtheorem{ex}{Example}[section]
\theoremstyle{definition}
\newtheorem{rmk}{Remark}[section]
\newtcbtheorem[number within=section]{thm}{Theorem}{before skip=10pt, breakable, detach title, leftrule=2mm, before upper={\tcbtitle\quad},coltitle=black, colback=black!3!white, colframe=black!10!white, fonttitle=\bfseries, arc=0mm, separator sign none, description delimiters parenthesis, terminator sign colon}{theo}
\newtcbtheorem[number within=section]{thm1}{Théorème}{before skip=10pt, breakable, detach title, leftrule=2mm, before upper={\tcbtitle\quad},coltitle=black, colback=black!3!white, colframe=black!10!white, fonttitle=\bfseries, arc=0mm, separator sign none, description delimiters parenthesis, terminator sign colon}{theo1}
\newtcbtheorem[number within=section]{propn}{Proposition}{before skip=10pt, breakable , coltitle=black, leftrule=2mm, detach title, before upper={\tcbtitle\quad}, colback=black!3!white,colframe=black!10!white,fonttitle=\bfseries, arc=0mm, separator sign none, description delimiters parenthesis, terminator sign colon}{propn} %questo serve per il ref
\newtcbtheorem[number within=section]{lem}{Lemma}{before skip=10pt, breakable, coltitle=black, detach title, leftrule=2mm, before upper={\tcbtitle\quad}, colback=black!3!white,colframe=black!10!white,fonttitle=\bfseries, arc=0mm, separator sign none, description delimiters parenthesis, terminator sign colon}{lem}
\newtcbtheorem[number within=section]{defn}{Definition}{before skip=10pt, coltitle=black, breakable, leftrule=2mm, coltitle=black, detach title, before upper={\tcbtitle\quad}, colback=black!3!white, colframe=black!10!white, fonttitle=\bfseries, arc=0mm, separator sign none, description delimiters parenthesis, terminator sign colon}{defn}
\newtcbtheorem[number within=section]{cor}{Corollary}{before skip=10pt, coltitle=black, breakable, detach title, leftrule=2mm, before upper={\tcbtitle\quad}, colback=black!3!white,colframe=black!10!white,fonttitle=\bfseries, arc=0mm, separator sign none, description delimiters parenthesis, terminator sign colon}{corol}
\newtcbtheorem[number within=section]{cor1}{Corollaire}{before skip=10pt, coltitle=black, breakable, detach title, leftrule=2mm, before upper={\tcbtitle\quad}, colback=black!3!white,colframe=black!10!white,fonttitle=\bfseries, arc=0mm, separator sign none, description delimiters parenthesis, terminator sign colon}{corol1}
\titleformat{\section}[display]{\fontsize{12}{0} \bfseries}{}{0pt}{\colorbox{black!15!white}{\parbox{\dimexpr\textwidth-2\fboxsep\relax}{\thesection \textcolor{black}{\quad#1}}}}[]
\titleformat{\subsection}[display]
{\itshape \normalsize \bfseries}{\thesubsection \textcolor{black}{\quad#1}}{-0.4cm}{}
\titleformat{name=\section,numberless}[display]{\fontsize{11.4}{0} \bfseries}{}{0pt}{\colorbox{black!15!white}{\parbox{\dimexpr\textwidth-2\fboxsep\relax}{\textcolor{black}{\quad#1}}}}[]
\titlespacing*{\section}{-0.8cm}{0.7cm}{0.2cm}[0pt]
{\setcounter{secnumdepth}{0}%
\addtocontents{toc}{\protect\setcounter{tocdepth}{0}\ignorespaces}}
{\setcounter{secnumdepth}{2}%
\addtocontents{toc}{\protect\setcounter{tocdepth}{2}\ignorespaces}}
\titleformat{\chapter}[display]
{\scshape\bfseries}
{}{10pt}
{\centering \LARGE \color{black!80!white} #1}
\titlespacing*{\chapter}{0pt}{0pt}{20pt}{}
\titleformat{\paragraph}[display]{\fontsize{11}{0}\selectfont \bfseries }{}{0pt}{#1}
\titlespacing*{\paragraph}{0.3cm}{0.4cm}{0.1cm}[0pt]
\setcounter{secnumdepth}{3}
\begin{document}
\section{Section}
\begin{thm}{}{}
Theorem.
\end{thm}
\begin{cor}{}{}
Corollary.
\end{cor}
\begin{rmk}
\end{rmk}
\begin{equation}
1+1=2
\end{equation}
\begin{rmk}
Remark.
\end{rmk}
\begin{equation}
2+1=3
\end{equation}
\begin{ex}
Another example.
\end{ex}
\begin{lem}{}{}
Lemma.
\end{lem}
\begin{defn}{}{}
Definition.
\end{defn}
\end{document}
So, referring to the above, I would like it to appear like "Theorem 0.1.1", "Corollary 0.1.2", "Remark 0.1.3", "Equation 0.1", "Remark 0.1.4", "Equation 0.2", "Example 0.1.5", "Lemma 0.1.6", "Definition 0.1.7". When changing the chapter, for example, I would like the numbering to start from "1.1.1" in the first section of the first chapter (for theorems etc.), while from 1.1 for equations. I hope I well explained what I'd need!