Drawing arrows from one Tcolorbox to another

You not provide any code what you tray so far, so, we can only guess and eventually retype your equations. Usually such service is not provided here, so the following proposition not directly addresses all your problems.

In case that you like to have tcolorboxes, the following may be a solution:

usepackage[most]{tcolorbox}

tcbset{on line,    
        boxsep=0pt, 
        colframe=gray,colback=white,
        highlight math style={enhanced}  % <---
        }

begin{document}
    [
tcbhighmath{begin{aligned} a=b c=dend{aligned}}
    longrightarrow
tcbhighmath{K=begin{bmatrix} a b end{bmatrix}}
    ]
end{document}

Note: contents of tcolorboxes you can organize by use all math environments defined in amsmath.

Another way is use of TikZ picture:

documentclass{article}
usepackage{amsmath}
usepackage{tikz}
usetikzlibrary{arrows.meta,
                positioning}

begin{document}
Some text

    begin{tikzpicture}[
every node/.style = {draw=gray, rounded corners, very thick}
                        ]
node (left)    {$begin{aligned} a=b c=dend{aligned}$};
node (right) [right=of left]
                {$begin{gathered} X = [text{some equation}]    
                        K_1=begin{bmatrix} a b end{bmatrix}
                        quad
                        K_2=begin{bmatrix} c d end{bmatrix}
                 end{gathered}$};
draw[-Straight Barb] (left) -- (right);
    end{tikzpicture}
end{document}

Addendum: you can also combine the both above solutions:

documentclass{article}
usepackage{amsmath}
usepackage[most]{tcolorbox}
usetikzlibrary{arrows.meta,
                positioning}

tcbset{on line,    % borrowed from https://tex.stackexchange.com/questions/568880/
        boxsep=0pt, % left=1pt,right=1pt,top=1pt,bottom=1pt,
        colframe=gray,colback=white, % or some other color of box background
        highlight math style={enhanced}  % <---
        }

begin{document}
    begin{tikzpicture}[
every node/.style = {inner sep=0pt}
                        ]
node (left)    {tcbhighmath{begin{aligned} a=b c=dend{aligned}}};
node (right) [right=of left]
                {tcbhighmath{begin{gathered} X = [text{some equation}]    
                        K_1=begin{bmatrix} a b end{bmatrix}
                        quad
                        K_2=begin{bmatrix} c d end{bmatrix}
                 end{gathered}}};
draw[-Straight Barb] (left) -- (right);
    end{tikzpicture}
end{document}

Result is similar as the second solution:

This is a mix between Zarko's Addendum and my answer to Add arrow between two tcolorboxes

The example is built into a beamer document. As overlay and remember picture are used, the arrow between boxes will appear after second compilation.

documentclass{beamer}
usepackage{amsmath}
usepackage[most]{tcolorbox}
usetikzlibrary{arrows.meta,
                positioning}

tcbset{on line,    % borrowed from https://tex.stackexchange.com/questions/568880/
        boxsep=0pt, % left=1pt,right=1pt,top=1pt,bottom=1pt,
        colframe=gray,colback=white, % or some other color of box background
        highlight math style={enhanced}  % <---
        }

begin{document}
begin{frame}{With tcolorbox}
tcbhighmath[remember as=left]{begin{aligned} a=b c=dend{aligned}}hspace{1cm}
tcbhighmath[remember as=right]{begin{gathered} X = [text{some equation}]    
                        K_1=begin{bmatrix} a b end{bmatrix}
                        quad
                        K_2=begin{bmatrix} c d end{bmatrix}
                 end{gathered}}
tikz[overlay, remember picture] draw[-Straight Barb] (left) -- (right);
end{frame}

end{document}