When hiding the label text using a space-character as label and a dedicated aria-label on the option for the undefined value, this results in an aria-misuse warning. This indicates we should consider always displaying the placeholder text for a select element.
See https://markus.oberlehner.net/blog/faking-a-placeholder-in-a-html-select-form-field/ for ideas on providing a placeholder text with reduced contrast instead of a fully-rendered item.
Note: this improves reading the blank item for Mozilla Firefox (last testet in Firefox v84). Firefox only announces "Item 1 of x" without the aria-label while iterating the expanded list because Firefox prioritizes the label, apparently. When the select element is collapsed, the item is read correctly.