Greyscale JPG - still 24bit = bigger size

Version:

Inkscape 1.2.2 (732a01da63, 2022-12-09)
(Did not test the 1.3 dev. version. If this problem has been already resolved, than I apologise.)

About:

The new JPG export is great, but incomplete, so it's currently useless for exporting non-coloured pictures.
The only way to achieve a small, good quality greyscale JPG is to export to non-compressed TIFF or PNG, than create JPG with an other program, deleting the big TIFF.
(Taking all together 15x so much time.)

Problem:

If you are creating a 2bit black&white or 8bit greyscale LOGOs, and trying to export it as JPG, it will still export as 24bit picture, taking more space than necessary, also takes more time to decompress.

Solution:

At Special export option window put a checkbox:
[x] Export as Greyscale

Optionally:

• Auto-recognise colour profile and check it automatically.

Thank you !

PS:

• TIFF export options should have a list with more explanation, which one is non-destructive.
  (Nobody can understand what's a "Group3 speed" or how to achieve compressed greyscale without data loss.)
• Maybe a simple checkbox to filter those.