I had my contacts and calendar on Google because that was how Android operated. When I noticed that the FLX1s had Nextcloud as an online account, I exported my contacts and calendar, set up Contacts and Calendar on my Nextcloud server, then imported the files. Next I set up my Nextcloud online account and I now have private Contacts and Calendar working, along with a method of sharing files between the FLX1s and my Linux infrastructure!