Google Drive web version does not support this. It always tries to return you 1 zip file.
But it is easy to make a JavaScript snippet which triggers the downloads separately.
var selecteds = document.querySelectorAll('[data-id][aria-selected="true"]');
selecteds.forEach(function (element) {
var dataId = element.getAttribute('data-id');
var frame = document.createElement("iframe");
frame.src = `https://drive.google.com/uc?id=${dataId}&export=download`;
frame.style = 'display: none';
element.appendChild(frame);
});
Select your files, open the developer console, paste and run the above 8 lines.
This is always much faster and simpler as Google allocates much less resource for file compression than file transfer. If you use it frequently, you may further turn it into a button by building a simple browser plugin.
$(function () {
var button = $('<div class="multiple-download">Multiple Downloads</div>');
button.prependTo('[role="toolbar"]:has([data-tooltip="Preview"])');
button.click(function () {
var selecteds = $('[data-is-doc-name][data-id][aria-selected="true"]');
selecteds.each(function () {
var dataId = $(this).attr('data-id');
var url = `https://drive.google.com/uc?id=${dataId}&export=download`;
var frame = $(`<iframe src="${url}" frameborder="0" style="display: none"></iframe>`);
frame.appendTo(this);
});
});
});