@alikon
This PR is OK for multilingual icons. I see no difference with sqli. Does it solve Postgres?

I suggest though, as I also modified the other 2 presets containing that code, to modify also modern.xml and menus.xml

LOL. Does it solve Postgres?

no unfortunately.... this is only a macroscopic one

My modification was to not use l.image but l.lang_code in the sql_select.
So, shall it also be modified in the sql_group ?

yes this is wrong from 3.x https://github.com/joomla/joomla-cms/blob/staging/administrator/components/com_menus/presets/joomla.xml#L233

where we use sql_group="a.id, m.language, l.image"

but the

a.id is not in the select list of fields

I mean, shall we not have also

sql_group="a.id, a.title, a.menutype, m.language, l.lang_code"

instead of

sql_group="a.id, a.title, a.menutype, m.language, l.image"

as we do not use l.image anymore.

yes, my bad, you are right

At looking at @Hackwar error here:
#25929 (comment)
and if I understand German OK, It looks like this could be the solution to the Posgres issue...

Please do it for the other presets too and test in Posgres

Now, can you check Postgres?

select a.id,a.title, a.menutype, CASE COALESCE(SUM(m.home), 0) WHEN 0 THEN '' WHEN 1 THEN CASE m.language WHEN '*' THEN 'class:icon-home' ELSE CONCAT('image:', l.lang_code) END ELSE 'image:mod_languages/icon-16-language.png' END AS icon
from my4_menu_types AS a
left join my4_menu AS m ON m.menutype = a.menutype AND m.home = 1 LEFT JOIN my4_languages AS l ON l.lang_code = m.language
where a.client_id = 0
group by a.id,a.title, a.menutype, m.language, l.lang_code
order by a.id DESC

currently i'm only able to test on postgresql console , and the resulting query is working now....
still not able to save an admin menu, but this is just another issue

let's wait to see if drone gets happy ;)

As for admin menu, see my comments on what is not solved in #25929 Summary of Changes

I have tested this item ✅ successfully on 01d1e58

Great!

I have tested this item ✅ successfully on 01d1e58

Thanks!