How to get Subcaption outside float working for landscape tables?

Question

I use the nice MWE displayed below to display a landscape table (found here: Tex: How to place table on new page.)

I have one big table (that's why landscape) which I want to split across multiple pages. So I want to split them in multiple tables with subcaption (I did not get longtable working as desired).

This MWE outputs:

Table 1: This should be table 1A

Table 2: This should be table 1B

(subcaption in alfabet, roman etc)

So my question is how to get subcaptions working outside floats.

I found this solution: Tex: Change caption in table from Table 2 to Table 1A => however if I combine both snippets it start to complain that subcaptions cannot be used outside floats.

    \documentclass{article}
    \usepackage{pdflscape}
    \usepackage{afterpage}
    \usepackage{capt-of}
    \usepackage{lipsum}
    \begin{document}
    \lipsum 
    \afterpage{%
        \clearpage
        \thispagestyle{empty}
        \begin{landscape}
            \centering 
            \begin{tabular}{llll}
                A & B & C & D \\
            \end{tabular}
            \captionof{table}{This should be table 1A}
        \end{landscape}
        \clearpage
    }
    \afterpage{
        \clearpage
        \thispagestyle{empty}
        \begin{landscape}
            \centering 
            \begin{tabular}{llll}
                E & F & G & H \\
            \end{tabular}
            \captionof{table}{This should be table 1B}
        \end{landscape}
        \clearpage
    }
    \lipsum 
    \end{document}