Stretch wide landscape table to fit page

• reorganize columns header, that columns can become narrower
• use S column type (defined in siunitx package
• remove resizebox{...}{...}, it make table almost unreadable, instead use tabular* with linewidth (which is in landscape equal to textheight) width and reduce font size to small

Based on guessing (in lack of information about your document preamble) see, if the following solution is what you looking for:

documentclass{article}
usepackage[margin=25mm]{geometry}
usepackage{pdflscape}
usepackage{booktabs, makecell}

usepackage{siunitx}

begin{document}
begin{landscape}
begin{table}
    caption {label{tab:Table 4 - MDI recursive prediction} This table demonstrates the MDI classification report for the individual corporate credit rating classes for an ET. Based on the balance between number of features and predictive performance in Table 3, precision, recall, F1 score and support are evaluated on 20 features for U.S. and global NonESG and ESG samples.}
small
setlengthtabcolsep{0pt}
    begin{tabular*}{linewidth}{@{extracolsep{fill}}l 
                                 *{4}{*{3}{S[table-format=1.4]}S[table-format=4.0]}
                                 }
        toprule
    & multicolumn{4}{c}{thead{U.S. NonESG}} 
            & multicolumn{4}{c}{thead{U.S. NonESG}}
                    & multicolumn{4}{c}{thead{GL NonESG}} 
                            & multicolumn{4}{c}{thead{GL ESG}}                     
    cmidrule(l){2-5}
    cmidrule(l){6-9}
    cmidrule(l){10-13}
    cmidrule(l){14-17}
    & {thead{precision}} & {thead{recall}} & {thead{F1 score}} & {thead{support}}   
    & {thead{precision}} & {thead{recall}} & {thead{F1 score}} & {thead{support}}
    & {thead{precision}} & {thead{recall}} & {thead{F1 score}} & {thead{support}}
    & {thead{precision}} & {thead{recall}} & {thead{F1 score}} & {thead{support}}
                                                                    
        midrule
AAA & 0.9766 & 0.9843 & 0.9804 & 127 
    & 1      & 1      & 1      & 55 
    & 1      & 1      & 1      & 34 
    & 1      & 1      & 1      & 27                         
AA+ & 0.9844 & 0.9403 & 0.9618 & 67 
    & 0      & 0      & 0      & 0 
    & 0.9167 & 0.9565 & 0.9362 & 23 
    & 0.9333 & 0.7778 & 0.8485 & 18                         
AA  & 0.9703 & 0.9729 & 0.9716 & 369 
    & 1      & 1      & 1      & 148 
    & 0.9254 & 0.9688 & 0.9466 & 64 
    & 0.9219 & 0.9833 & 0.9516 & 60                         
AA- & 0.9543 & 0.9730 & 0.9636 & 408 
    & 1      & 1      & 1      & 96 
    & 0.9815 & 0.9578 & 0.9695 & 166 
    & 1      & 0.9645 & 0.9819 & 169                        
A+  & 0.9700 & 0.9739 & 0.9719 & 995 
    & 0.9968 & 1      & 0.9984 & 309 
    & 0.9804 & 0.9709 & 0.9756 & 309 
    & 0.9619 & 0.9806 & 0.9712 & 309                        
A   & 0.9696 & 0.9639 & 0.9667 & 1357 
    & 0.9684 & 0.9629 & 0.9656 & 350 
    & 0.9463 & 0.9559 & 0.9511 & 295 
    & 0.9353 & 0.9455 & 0.9403 & 275                        
A-  & 0.9577 & 0.9583 & 0.9580 & 1464 
    & 0.9790 & 0.9689 & 0.9739 & 482 
    & 0.9618 & 0.9658 & 0.9638 & 730 
    & 0.9772 & 0.9646 & 0.9709 & 622                        
        addlinespace
BBB+ 
    & 0.9558 & 0.9663 & 0.9610 & 1901 
    & 0.9724 & 0.9830 & 0.9776 & 823 
    & 0.9716 & 0.9716 & 0.9716 & 1090 
    & 0.9748 & 0.9737 & 0.9743 & 914                        
BBB & 0.9613 & 0.9582 & 0.9597 & 2438 
    & 0.9758 & 0.9697 & 0.9727 & 956 
    & 0.9537 & 0.9683 & 0.9609 & 914 
    & 0.9674 & 0.9744 & 0.9709 & 821                        
BBB- 
    & 0.9541 & 0.9508 & 0.9524 & 2031 
    & 0.9701 & 0.9726 & 0.9714 & 802 
    & 0.9592 & 0.9613 & 0.9603 & 930 
    & 0.9708 & 0.9708 & 0.9708 & 754                        
BB+ & 0.9347 & 0.9474 & 0.9410 & 1406 
    & 0.9560 & 0.9613 & 0.9587 & 543 
    & 0.9434 & 0.9488 & 0.9461 & 527 
    & 0.9504 & 0.9637 & 0.9570 & 358                        
BB  & 0.9597 & 0.9413 & 0.9504 & 1721 
    & 0.9415 & 0.9489 & 0.9452 & 509 
    & 0.9667 & 0.8906 & 0.9271 & 521 
    & 0.9474 & 0.9375 & 0.9424 & 288                        
BB- & 0.9467 & 0.9554 & 0.9510 & 2397 
    & 0.9712 & 0.9637 & 0.9674 & 524 
    & 0.9268 & 0.9552 & 0.9408 & 424 
    & 0.9474 & 0.9083 & 0.9274 & 218                        
B+  & 0.9351 & 0.9496 & 0.9423 & 2261 
    & 0.9728 & 0.9831 & 0.9779 & 473 
    & 0.9250 & 0.9250 & 0.9250 & 320 
    & 0.9106 & 0.9412 & 0.9256 & 119                        
B   & 0.9423 & 0.9262 & 0.9342 & 1341 
    & 0.9490 & 0.9442 & 0.9466 & 197 
    & 0.9157 & 0.9373 & 0.9264 & 255 
    & 0.8830 & 0.8925 & 0.8877 & 93                         
B-  & 0.9010 & 0.9151 & 0.9080 & 577 
    & 0.9655 & 0.8889 & 0.9256 & 63 
    & 0.9409 & 0.8925 & 0.9161 & 214 
    & 0.9833 & 0.9365 & 0.9593 & 63                         
        addlinespace
CCC+ 
    & 0.9136 & 0.8627 & 0.8874 & 233 
    & 0.9730 & 0.9730 & 0.9730 & 37 
    & 0.7843 & 0.8333 & 0.8081 & 48 
    & 0.8235 & 0.9333 & 0.8750 & 30                         
CCC & 0.8701 & 0.7976 & 0.8323 & 84 
    & 1      & 1      & 1      & 9 
    & 0.7857 & 0.9429 & 0.8571 & 35 
    & 0.8235 & 1      & 0.9032 & 14                         
CCC- 
    & 0.8864 & 0.7800 & 0.8298 & 50 
    & 1      & 0.9412 & 0.9697 & 17 
    & 0.9231 & 1      & 0.9600 & 36 
    & 1      & 1      & 1      & 6                          
CC  & 0.9762 & 0.8200 & 0.8913 & 50 
    & 1      & 1      & 1      & 11 
    & 0.9130 & 0.7    & 0.7925 & 30 
    & 0.875  & 0.7    & 0.7778 & 10                         
        addlinespace
SD  & 0.5556 & 0.7143 & 0.6250 & 7 
    & 0      & 0      & 0      & 0 
    & 0.9231 & 1      & 0.9600 & 12 
    & 0.5    & 0.3333 & 0.4    & 3                          
D   & 0.9485 & 0.8846 & 0.9154 & 104 
    & 1      & 1      & 1      & 4      
    & 0.8889 & 1      & 0.9412 & 32 
    & 0.8333 & 0.8333 & 0.8333 & 6                          
        midrule
accuracy 
    & 0.9506 & 0.9506 & 0.9506 & {0.9506} 
    & 0.9708 & 0.9708 & 0.9708 & {0.9708} 
    & 0.9518 & 0.9518 & 0.9518 & {0.9518} 
    & 0.9612 & 0.9612 & 0.9612 & {0.9612}                   
macro avg 
    & 0.9284 & 0.9153 & 0.9207 & {21388} 
    & 0.9796 & 0.9731 & 0.9762 & {6408} 
    & 0.9288 & 0.9410 & 0.9334 & {7009} 
    & 0.9145 & 0.9052 & 0.9077 & {5177}                     
weighted avg 
    & 0.9507 & 0.9506 & 0.9506 & {21388}  
    & 0.9708 & 0.9708 & 0.9708 & {6408}   
    & 0.9522 & 0.9518 & 0.9517 & {7009}   
    & 0.9614 & 0.9612 & 0.9611 & {5177}                       
        bottomrule
    end{tabular*}
end{table}
    end{landscape}
end{document}