I find one problem with the Joomla 4 Helix Template. It still has the old file structure for the template so USER.CSS does not land up in the "/media/templates/site" folder as per latest J4 templates. e.g:
Helix Template File Structure:
/templates/shaper_helixultimate
-- css
---- presets
---- bootstrap.min.css
---- etc.
---- etc.
---- user.css
-- features
-- fonts
etc.
etc.
Other J4 Template (e.g. Cassiopeia) file structure
/templates/cassiopeia
-- html
-- component.php
etc.
/media/templates/site/cassiopeia
-- css
---- user.css
---- etc.
-- images
-- js
-- scss