Here’s another solution.
Edit /www/nextcloud/data/.htaccess like below:
<ifModule mod_authz_core.c>
Require all denied
</ifModule>
<FilesMatch ".ocdata">
<IfModule mod_authz_core.c>
Require all granted
</IfModule>
</FilesMatch>
# line below if for Apache 2.2
<ifModule !mod_authz_core.c>
deny from all
Satisfy All
</ifModule>
# section for Apache 2.2 and 2.4
<ifModule mod_autoindex.c>
IndexIgnore *
</ifModule>