.htaccess resolution warnings on ReadyNAS instance

I am attempting to correct warnings in my Nextcloud instance. It is installed on a ReadyNAS 214, running ReadyNAS OS 6.10 (Debian Jessie, with Apache 2.4 and PHP 7.2).

Path to Apache Document Root is: /frontview/dashboard
Path to Nextcloud application is: /apps/nextcloud/web
URL of Nextcloud is: https://gjschaller.homeftp.net/nextcloud/

I’ve added the following to an .htaccess file in the Apache document root (Brackets edited for display):

{IfModule mod_rewrite.c}
RewriteEngine on
RewriteRule ^/.well-known/host-meta /nextcloud/public.php?service=host-meta [QSA,L]
RewriteRule ^/.well-known/host-meta.json /nextcloud/public.php?service=host-meta-json [QSA,L]
RewriteRule ^/.well-known/webfinger /nextcloud/public.php?service=webfinger [QSA,L]
RewriteRule ^/.well-known/carddav /nextcloud/remote.php/dav/ [R=301,L]
RewriteRule ^/.well-known/caldav /nextcloud/remote.php/dav/ [R=301,L]

I’ve also added a https://gjschaller.homeftp.net/test.html file, which I can browse, so I know the path is correct, and I have confirmed mod_rewrite is enabled via phpinfo. The warnings still persist, however.

Any idea why Nextcloud may not be seeing the .htaccess changes?