Keep accented characters while highlighting text (wrapping in <span> tags)

I am using the following code to search and highlight accented text. The problem I am facing is that it removes accented text while highlighting. Is there anyway to keep accents?

echo highlightTerm("Would you like a café, Mister Kàpêk?", "kape caf");

function highlightTerm($text, $keyword) {
    $text = iconv('utf-8', 'ISO-8859-1//IGNORE', Normalizer::normalize($text, Normalizer::FORM_D));
    $words = explode(" ", $keyword);
    $p = implode('|', array_map('preg_quote', $words));
    return preg_replace(
        "/($p)/ui", 
        '<span style="background:yellow;">$1</span>', 
        $text
    );
}

Instead of normalizing the text, you can use the tedious approach of creating a dynamic, accent-agnostic regex pattern and then directly perform replacements on the input string.

The regex map (based on the second code block of this answer):

define(
    'ACCENT_MAP',
    [
        "A" => "[AАĂǍĄÀÃÁÆÂÅǺĀא]",
        "B" => "[BБבÞ]",
        "C" => "[CĈĆÇЦצĊČץ]",
        "D" => "[DДĎĐדÐ]",
        "E" => "[EÈĘÉËÊЕĒĖĚĔЄƏע]",
        "F" => "[FФƑ]",
        "G" => "[GĞĠĢĜГגҐ]",
        "H" => "[HחĦХĤה]",
        "I" => "[IIÏÎÍÌĮĬIИĨǏיЇĪІ]",
        "J" => "[JЙĴ]",
        "K" => "[KĸכĶКך]",
        "L" => "[LŁĿЛĻĹĽל]",
        "M" => "[MמМם]",
        "N" => "[NÑŃНŅןŊנʼnŇ]",
        "O" => "[OØÓÒÔÕОŐŎŌǾǑƠ]",
        "P" => "[PפףП]",
        "Q" => "[Qק]",
        "R" => "[RŔŘŖרР]",
        "S" => "[SŞŚȘŠСŜס]",
        "T" => "[TТȚטŦתŤŢ]",
        "U" => "[UÙÛÚŪУŨƯǓŲŬŮŰǕǛǙǗ]",
        "V" => "[VВו]",
        "Y" => "[YÝЫŶŸ]",
        "Z" => "(?:Z|ŹŽŻЗז",
        "a" => "[aаăǎąàãáæâåǻāא]",
        "b" => "[bбבþ]",
        "c" => "[cĉćçцצċčץ]",
        "ch" => "(?:ch|ч)",
        "d" => "[dдďđדð]",
        "e" => "[eèęéëêеēėěĕєəע]",
        "f" => "[fфƒ]",
        "g" => "[gğġģĝгגґ]",
        "h" => "[hחħхĥה]",
        "i" => "[iiïîíìįĭıиĩǐיїīі]",
        "j" => "[jйĵ]",
        "k" => "[kĸכķкך]",
        "l" => "[lłŀлļĺľל]",
        "m" => "[mמмם]",
        "n" => "[nñńнņןŋנʼnň]",
        "o" => "[oøóòôõоőŏōǿǒơ]",
        "p" => "[pפףп]",
        "q" => "[qק]",
        "r" => "[rŕřŗרр]",
        "s" => "[sşśșšсŝס]",
        "t" => "[tтțטŧתťţ]",
        "u" => "[uùûúūуũưǔųŭůűǖǜǚǘ]",
        "v" => "[vвו]",
        "y" => "[yýыŷÿ]",
        "z" => "[zźžżзזſ]",
        "ae" => "(?:ae|[ÄǼäæǽ])",
        "ch" => "(?:ch|[Чч])",
        "ij" => "(?:ij|[ijIJ])",
        "ja" => "(?:ja|[яЯ])",
        "je" => "(?:je|[Ээ])",
        "jo" => "(?:jo|[ёЁ])",
        "ju" => "(?:ju|[юЮ])",
        "oe" => "(?:oe|[œŒöÖ])",
        "sch" => "(?:sch|[щЩ])",
        "sh" => "(?:sh|[шШ])",
        "ss" => "(?:ss|[ß])",
        "ue" => "(?:ue|[Ü)",
        "zh" => "(?:zh|[Жж])"
    ]);

Code: (Demo)

function highlightTerm($text, $keyword) {
    $regex = implode(
        '|',
        array_map(
            fn($w) => strtr(preg_quote($w), ACCENT_MAP),
            explode(" ", $keyword)
        )
    );
    return preg_replace(
               "#$regex#ui",
               '<span style="background:yellow;">$0</span>',
               $text
           );
}

echo highlightTerm("Would you like a café, Mister Kàpêk?", "kape caf");

Output:

Would you like a <span style="background:yellow;">caf</span>é, Mister <span style="background:yellow;">Kàpê</span>k?