Dynamiclly create DOM element based on the value:

function PokemonCollection({ as: As = 'ul', renderItem }) {
  return (
    <As>{initialCollection.read().results.map(renderItem)}</As>;
  )
}

 

<PokemonCollection
  as="ul"
  renderItem={pokemon => (
    <li key={pokemon.name}>
    <button type="button" 
      onClick={() => 
        startTransition(() => 
          setPokemonResource(
              suspensify(fetchPokemon(pokemon.id))))}>
      {pokemon.name}
    </button>
    </li>
  )}
/>