Why is my element disappearing for no reason?

const url = "https://pokeapi.co/api/v2/pokemon/";

const sprite3dElement = document.querySelector(".pokemon-3Dmodel img");

const pokemonList = document.querySelector(".pokemon-list");
const shinyButton = document.querySelector(".shiny-button");

const premierPokemon = 1;
const dernierPokemon = 151;
const nbPokemon = dernierPokemon - premierPokemon + 1;

window.addEventListener("load", getPokedata);

function getPokedata() {
  const pokemonData = []; // array to store each Pokemon's data

  for (let i = premierPokemon; i <= dernierPokemon; i++) {
    const finalUrl = url + i;
    fetch(finalUrl)
      .then((response) => response.json())
      .then((data) => {
        pokemonData[i - premierPokemon + 1] = data; // store the data for each Pokemon in the correct order
      })
      .then(() => {
        if (pokemonData.length === nbPokemon + 1) {
          // if we have fetched all the Pokemon data, generate the cards in the correct order
          pokemonData.forEach((data) => {
            generateCard(data);
          });
          betterPokemonCards();
          toggleShiny();
        }
      });
  }
}

function generateCard(data) {
  console.log(data);
  const dex_number = data.id;
  const name = data.name;
  const sprite3D = data.sprites.other["official-artwork"].front_default;
  const sprite3DShiny = data.sprites.other["official-artwork"].front_shiny;
  const sprite2D = data.sprites.versions["generation-viii"].icons.front_default;

  pokemonList.innerHTML += ` <li class="pokemon${
    dex_number == dernierPokemon ? " pokemon-active" : ""
  }" data-sprite3D="${sprite3D}" data-shiny3D="${sprite3DShiny}" data-id="${dex_number}">
  <div>
  <div class="pokemon__sprite">
  <img src="${sprite2D}" alt="sprite">
  </div>
  <p class="pokemon__num">No. <span class="pokemon__num--field">${dex_number}</span></p>
  </div>
  <p class="pokemon__name">${name}</p>
  <div class="pokeball">
  <img src="images/pokeball.png" alt="pokeball">
  </div>
  </li>
  `;
  sprite3dElement.src = sprite3D;
}

function betterPokemonCards() {
  let pokemons = document.querySelectorAll(".pokemon");

  //adds one or two 0 to the dex number if it is less than 10 or 100
  pokemons.forEach((pokemon) => {
    let dex_entry =
      pokemon.firstElementChild.lastElementChild.lastElementChild.innerText;
    if (dex_entry.length == 1) {
      pokemon.firstElementChild.lastElementChild.lastElementChild.innerText =
        "00" + dex_entry;
    } else if (dex_entry.length == 2) {
      pokemon.firstElementChild.lastElementChild.lastElementChild.innerText =
        "0" + dex_entry;
    }
    //adds an event listener to each pokemon so that when you click on it, it adds the class pokemon-active
    pokemon.addEventListener("click", () => {
      sprite3dElement.src = pokemon.getAttribute("data-sprite3D");
      pokemons.forEach((pokemon) => {
        pokemon.classList.remove("pokemon-active");
      });
      pokemon.classList.add("pokemon-active");
    });
  });
}

:root {
  --attachment: fixed;
  --degrees: 115deg;
  --colorStop-1: 50%;
  --colorStop-2: calc(var(--colorStop-1) + 100px);
}
*,
*::before,
*::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}
img {
  width: 100%;
}
body {
  font-family: "Noto Sans KR", sans-serif;
  background-color: #fff;
  color: #282828;
  background-image: linear-gradient(
      var(--degrees),
      transparent var(--colorStop-1),
      #fe4d3e var(--colorStop-1) var(--colorStop-2),
      #fa7246 var(--colorStop-2)
    ),
    radial-gradient(
      circle at 20% 70%,
      rgb(239 208 234 / 0.9),
      rgb(234 201 242 / 0.6),
      rgb(231 238 197 / 0.6),
      rgb(205 240 219 / 0.6),
      rgb(231 237 245 / 0.6)
    );
  background-attachment: var(--attachment);
  min-height: 100vh;
  overflow: hidden;
}
.header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  background-image: linear-gradient(
    115deg,
    rgba(50 0 0 / 0.15) var(--colorStop-1),
    rgb(53 53 53) var(--colorStop-1)
  );
  background-attachment: var(--attachment);
  margin-top: 10px;
}
.header h1 {
  font-size: 2rem;
  padding-left: 1rem;
}
.header p {
  font-size: 1.5rem;
  color: white;
  padding-right: 13%;
}
.pokedex {
  position: relative;
  display: flex;
  justify-content: flex-end;
}
.shiny-button {
  position: absolute;
  left: 20px;
  top: 20px;
  width: 5rem;
  filter: drop-shadow(5px 5px 0 rgba(130, 217, 211, 0.408));
  cursor: pointer;
}
div:has(.pokemon-3Dmodel) {
  display: flex;
  justify-content: center;
  align-items: center;
  margin-inline: auto;
}
.pokemon-3Dmodel {
  filter: drop-shadow(8px 8px 3px #39393951);
}
.pokemon-list {
  width: clamp(360px, 100%, 520px);
  height: calc(100vh - 56px);
  display: flex;
  overflow-y: scroll;
  overflow-x: visible;
  flex-direction: column;
  gap: 15px;
  padding: 20px 10px 20px 0;
  margin-right: 20px;
  border: 3px solid gold;
  position: relative;
}
.pokemon-list::before {
  content: "+";
  position: absolute;
  top: 0;
  left: -1rem;
  font-size: 3rem;
  border: 3px solid blue;
  line-height: 1em;
}
.pokemon {
  display: flex;
  justify-content: space-between;
  align-items: center;
  text-transform: capitalize;
  padding: 0 10px 0 0;
  color: black;
  font-weight: 500;
  font-size: 1.3rem;
  border-radius: 100vw;
  cursor: pointer;
}
.pokemon:hover,
.pokemon-active {
  background-image: linear-gradient(115deg, #f04f17 45%, black 45%);
  color: white;
}
.pokemon-active {
  position: relative;
}
.pokemon-active .pokeball {
  animation: rotate 1600ms infinite linear;
}

@keyframes rotate {
  to {
    rotate: 360deg;
  }
}
.pokemon > div:first-of-type {
  display: flex;
  align-items: center;
}
.pokemon__sprite {
  width: 60px;
  scale: 1.2;
  transform-origin: bottom;
  margin-inline: 10px;
}
.pokemon__num {
  display: flex;
}
.pokemon__num--field {
  margin-left: 0.5rem;
}
.pokeball {
  width: 25px;
  height: 25px;
  display: flex;
}

<main>
  <div class="header">
    <h1>Pokédex</h1>
    <p>By Number</p>
  </div>
  <section class="pokedex">
    <div>
      <div class="pokemon-3Dmodel">
        <img src="">
      </div>
    </div>
    <ul class="pokemon-list">
    </ul>
  </section>
</main>