Lz,
This does not create a UTF-8 tab delimited text file on a Windows machine either!
I know if you google you will find this tip again and again. It's a battle against windmills, but please help end this fake.
To check the result of what is actually saved, we first need an Excel file that contains characters encoded with UTF-8 that look different in ANSI. I live in Germany, we have a lot of these chars:

https://www.dropbox.com/s/gm0ie39wceottr9/UTF8.xlsx?dl=1
Now let us save this file as UTF-8 CSV file
https://www.dropbox.com/s/4cmgbr1hsju0hyr/UTF8.csv?dl=1
In Germany, the semicolon is the delimiter in a CSV, if you save the file I guess you have a comma as delimiter, but the chars € and ü are encoded as € and ü as we can see within a hex editor:

The first 3 bytes is a BOM (byte order mark) that means this CSV is really a BOM-UTF8-CSV.
If you want a UTF8-CSV without the BOM you can use my AddIn on a Windows machine. It did not work on a Mac!
https://www.dropbox.com/s/m7qdh5gs3wqb99r/CSV.xla?dl=1
A CSV without the BOM contains the same chars with the same encoding, just the first 3 bytes are missing:
https://www.dropbox.com/s/1umrgfq8zaf1czq/UTF8%20without%20BOM.csv?dl=1

If we save the file as tab delimited file as you suggested we get this:
https://www.dropbox.com/s/ydki48jiqr1oyyk/UTF8.txt?dl=1

If you look closer to this last screenshot you'll see "Windows (ANSI)" below "Extras" which means the chars you see on the right edge are decoded in ANSI. And as we can see the € und ü char means that is an ANSI encoded file.
So why does this not work:

This window is titled "Web Options" and if we press F1 we get here:
https://support.microsoft.com/en-us/office/web-page-options-59620e8a-7244-41cc-9867-b9d20e64e653
[quote]
Save this document as Select the encoding in which you want the Web page to be saved.
[/quote]
This option works for .htm and .html files only, not for other file types.
I'm not a Mac user, but my limited knowledge of the Mac leads me to believe that there is no way to create a tab-delimited UTF-8 file, because of the limitations on a Mac.
Maybe there is a way to use a macro to make the translation of some chars and convert the whole sheet. And if we save that as ANSI tab delimited text file it might be correctly decoded as UTF-8. I've never tried it, just an idea.
Andreas.