lower temps work partially afaik and they will never fully dry the silica gel. You should aim for above 100°C
If you are concerned about safety have one dedicated oven dish for the silica gel and ventilate your oven and kitchen thoroughly after a session.
I personally really like sftpgo and I mount it via webdav.
I used seafile first, then nextcloud. Each for a couple of years and had significant problems with both.