Script werkt in PHP 7.4 maar niet in 8.0

$tebehalentotaal=str_replace(',' , '.',$tebehalentotaal);
$behaaldepunten=str_replace(',' , '.',$behaaldepunten);

$ditgeeft60bij=$tebehalentotaal*0.6;
$foutperpunt=($tebehalentotaal-$ditgeeft60bij)/4;
$foutperpunt=number_format($foutperpunt,2,".",",");
$ditgeeft55bij=number_format($ditgeeft60bij,2,".",",");
$cijfer=10-(($tebehalentotaal-$behaaldepunten)*(4/($tebehalentotaal-$ditgeeft60bij)));
$cijfer=max($cijfer,1);
$cijfer=number_format($cijfer,2,".",",");
$date=date("d/M/Y");
$url = (isset($_SERVER['HTTPS']) && $_SERVER['HTTPS'] === 'on' ? "https" : "http") . "://$_SERVER[HTTP_HOST]$_SERVER[REQUEST_URI]";


$tableresult="";

$tableresult.="<table class='uk-table uk-table-striped uk-table-small'>";
$tableresult.="<thead>";
$tableresult.="<tr>";
$tableresult.="<th style='color:#0bc9eb;font-weight:bold'>Goed</th>";  
$tableresult.="<th style='color:#0bc9eb;font-weight:bold'>Fout</th>";  
$tableresult.="<th style='color:#0bc9eb;text-align:right;font-weight:bold'>Cijfer</th>";

$tableresult.="</tr>";
$tableresult.="</thead>";


//$i from 0 to te behalen totaal,increasing by half:
for($i=0;$i<=$tebehalentotaal;$i+=0.5){

//resultaat
$resultaat=(10-($i*(4/($tebehalentotaal-$ditgeeft60bij))));

if($resultaat<1){
$resultaat="1.0";
}
else{
$resultaat=number_format($resultaat,1,".",",");
}

//resultaat heel color
if($resultaat>=6){
$resultcolor="#47d147";
}
else{
$resultcolor="#ff471a";
}

//punten
$tableresult.="<tr>";
$tableresult.="<td style='color:#ffffff'>".($tebehalentotaal-$i)."</td>";  

//fouten
$tableresult.="<td style='font-size:16px'>".($i)."</td>"; 

//resultaat
$tableresult.="<td style='color:$resultcolor;text-align:right'>".$resultaat."</td>";

}
$tableresult.="<tfoot>";
$tableresult.="<tr>";
$tableresult.="<th style='color:#0bc9eb;font-weight:bold'>Goed</th>";  
$tableresult.="<th style='color:#0bc9eb;font-weight:bold'>Fout</th>";  
$tableresult.="<th style='color:#0bc9eb;text-align:right;font-weight:bold'>Cijfer</th>";

$tableresult.="</tr>";
$tableresult.="</foot>";
$tableresult.="</table>";