Bingo, I was halfway: figured out the ini module iso an edit, but didn’t know the phpenmodcmd!
Another little detail is that I had to add a cache dir (uid/git www-data):
gencache_init: Failed to create directory: /var/www/.cache/samba - Permission denied
After re-running the scan, success at last:
root@houtje:/var/www/nextcloud# sudo -u www-data php occ files:scan --all
Starting scan for user 1 out of 5 (admin)
Another process is already scanning '/admin'
[...]
Starting scan for user 5 out of 5 (samuel)
+---------+-------+-----+---------+---------+--------+--------------+
| Folders | Files | New | Updated | Removed | Errors | Elapsed time |
+---------+-------+-----+---------+---------+--------+--------------+
| 1441 | 53002 | 0 | 0 | 0 | 0 | 00:02:58 |
+---------+-------+-----+---------+---------+--------+--------------+
As I understand it, this solves the NC + SMB error caused by icewind relying on an outdated SMB client, by building and adding the latest php-smbclient extension to bypass the smbclient cmdline utility.