Even "appliance" devices can be used in a manner which increases freedom, e.g. retain iPad flexibility and reliability while using it as a thin client for self-hosted content and services on FreeNAS/TrueNAS on open hardware. Choose iOS apps (e.g. Omni, 2Do, DevonThink, GoodReader, Codebook, Netnewswire, LumaFusion, Textastic, Working Copy, Secure Shellfish, PhotoSync, Jump, Screens) which support synchronization protocols like CalDAV, WebDAV, ssh/scp, SMB, DLNA, RDP etc. With the recently introduced iSH (user-space Linux) on iOS, more integration options are available. You can also use an iOS remote desktop with mouse/keyboard to drive remote desktops and VMs that have less OS/app restrictions.