Non-Ascii Filenames are not Synced!

it seems all files that contain a non-ascii character in their path are not properly synced.
either not synced at all, or the filename truncated at will.
this is serious. and urgent!

update to this: on further inspection - occ files:scan throws an error: function json_encode does not exist!

can not find out why- as the current PHP installation 7.4.20 has the json-encode function available and testing outside of occ context does not produce any problems…

non-ascii filenames issues and this possibly related…

the issue shows up quite often in the forum - and people point at permission issue.
after deeper research, i can clearly say: there must be other issues as well.
my permissions are OK, and yet i can not delete certain files.

the context can be described as:
filenames have been JAPANESE (= non-ascii) when uploaded/synced originally.
at the time or later, OCC threw error that JSON_ENCODE function was not defined
then, JSON_ENCODE worked well in BROWSER/SERVER (=APACHE) context, but NOT from CLI
APACHE and CLI used the same php.ini file
i could not identify ANY REASON why CLI would not have access to the JSON commands (MODULE)
hence, i made a clean re-install of PHP and ALL required modules
at that point CLI recognized JSON commands (MODULE)
i was hoping that this would solve the issue - but that was not the case

hence, in conclusion, i assume that the PATH on record (in the NEXTCLOUD DB) must be corrupted, what leads, on attempting to delete the file from the WEB interface to the error message <ERROR deleting file ‘xxx’>
BTW: changing the filename to ASCII characters only was possible, but did not solve the <FILE_DELETION> issue.
the containing folder hierarchy can not be deleted/moved/renamed at any level

now i am left with the problem on how to REPAIR the proper path, if at all possible.

hope this helps the DEVELOPERS to identify the BUG and come up with a FIX, such as

() complete acceptance of UTF-8 paths
() warning if necessary functions, such as JSON_ENCODE are not available => more actionable DIAGNOSTICS/ERROR REPORTING
() update PATHS via OCC, such as